Document [original]

Amphiphilic Block Copolymers as Agents for

Solublisation and Modification of Vesicle

Phases

vorgelegt von

Diplom Chemikerin

HSIN-YI LIU

aus Chia-yi, Taiwan

von der Fakultät II- Mathematik und Naturwissenschaften

der Technischen Universität Berlin

zur Erlangung des akademischen Grades

Doktor der Naturwissenschaften

- Dr.rer.nat. -

genehmigte Dissertation

Promotionsausschuss:

Vorsitzender: Prof. Dr. Thorsten Ressler

Berichter : Prof. Dr. Michael Gradzielski

Berichter : Prof. Dr. Joachim Koetz ( Uni Postdam)

Tag der wissenschaftlichen Aussprache: 18. Dezember 2012

Berlin 2013

D83

Zusammenfassung

Das Thema dieser Dissertation war die Untersuchung der Solubilisation von Ö len

unterschiedlicher Polarität in wässrigen Lösungen amphiphiler Copolymere und deren

Einfluss auf die Eigenschaften von Vesikeln und Vesikelgelen. Im ersten Teil wird der

Effekt der Ö lzugabe auf die Thermodynamik des Mizellierungsprozesses mit Hilfe von

DSC und cmc Fluoreszenzmessungen speziell am Beispiel des Triblock Copolymers F108

diskutiert, einem PEO-PPO-PEO Blockcopolymers. Hier zeigt sich, dass generell die

Anwesenheit eines Ö ls diesen Prozess befördert, der auf der Dehydratisierung der PPO

Einheit mit steigender Temperatur basiert, wobei dies allerdings nur auf Ö le ausreichender

Polarität zutrifft, während z. B. Alkane gar nicht solubilisert werden. Im Detail hängt aber

die Absenkung der Mizellierungstemperatur und die Zunahme der Umwandlungsenthalpie

stark von der Polarität des Ö ls ab und für den Zusatz des Homopolymers PPO beobachtet

man sogar gar keine Veränderung der Mizellierungstemperatur, was darauf zurückgeführt

werden kann, dass hier keine zusätzliche Hydrophobisierung des sich bildenden

Mizellkerns erfolgen kann. Die vorliegenden mizellaren Strukturen wurden dann mit Hilfe

von DLS und SANS charakterisiert wobei sich zeigte, dass die sich ausbildenden

Copolymermizellen auch entsprechend größer werden bei Zusatz der polaren Ö le.

Im zweiten Teil wurde der Einfluss unterschiedlicher amphiphiler Polymer auf Struktur und

Stabilität unilamellarer Vesikel aus dem Phospholipid DMPC oder einem Diesterquat

untersucht. Die durch Extrusion erhaltenen Vesikel wurden dann über einen längeren

Zeitraum mit Hilfe von DLS beobachtet und diese Untersuchungen zeigten eine Reduktion

der Stabilitätsdauer mit zunehmendem Polymergehalt, wobei dieser Effekt allerdings stark

von der Art des Polymers abhing. Die Destabilisierung ist umso stärker, je stärker das

Polymer in der Lage ist unterschiedliche Vesikel zu verbrücken. Schließlich wurde auch

der Einfluss der Polymere auf die Permeabilität der Vesikelmembranen untersucht, was

mit Hilfe der Stopped-Flow Methode und einer dabei ablaufenden Komplexierungsreaktion

erfolgte. Der Polymerzusatz kann dabei zu einer Verlangsamung oder Beschleunigung

des Austausches führen. Schließlich wurde noch der Einfluss solcher Polymer auf die

rheologischen Eigenschaften von Vesikelgelen aus dichtgepackten multilamellaren

Vesikeln (MLVs) betrachtet. Hierbei zeigte sich, dass die verbrückenden Polymere eine

deutlich stärkere Erhöhung der elastischen Eigenschaften als nichtverbrückendes F108

ergaben.

Abstract

The investigation of micelle, vesicle and gel phases are all covered in this doctor

dissertation. The thermal appearance of micelle phases is the main point in the first part.

The triblock copolymer F108 is selected as the parent solution to be analysed by the

methods of calorimetric instrument, because its amphiphilic character is sensitive to the

temperature. The presence of selecting mixtures influences the thermal appearance of

fixed F108 solutions; furthermore, the size of micelle phases is analysed by the scattering

methods DLS and SANS. The size of the particles depends on temperature; however, not

affected by the presence of mixture.

In the second part discusses the stability of the small unilammelar vesicles (SUVs) in

aqueous solution. The phospholipids DMPC and diesterquat CR3099 are selected as

parent solution. They form large unilammelar vesicles (LUVs) as different range of radius

especially for DMPC solution. The size is controlled by means of extrusion with 100 nm

poly carbonate filter. The stability of the small vesicles is investigated by DLS. The results

show that small vesicles of DMPC are not stable, while those of CR3099 are stable for a

period of at least six month. Each of small vesicles for DMPC tends to aggregate to form

large vesicles in solution. The times of extrusion, in the presence of copolymer could be

the factors of reducing and extending the time of stable small vesicles. The permeability of

DMPC vesicles is determined by the Stopped Flow Technique with help of FeSCN2+ and F-

ions. The relaxation time τ is reduced in the presence of copolymer 10R5 and extended

in the presence of L35. The thickness of uniamellar vesicles is analysed by model of

Krotky-Porod from the experimental SANS date.

The final part focuses on gel solutions. The vesicle gels of zwiter ionic TDMAO, ionic

TTABr and 1-Hexanol at different ratios appear as different phases of gel. The various

ratios of these chemicals form the multilamellar vesicles (MLVs), which were found by

Freeze-fracture electron microscopy [1]. These gel solutions, which are already formed by

multilamellar vesicles, include copolymers such as 10R5, Rewopal 6000 and F108. They

are analysed by rheology instruments.

Content

1. Introduction..........................................................................................................7

1-1 Packing Parameter…………………………………………………………………...7

1-2 Hildebrandt Parameter………………………………………………………...........9

1-3 Thermodynamics of micellization………………………………………………….10

1-4 Cloud point…………………………………………………………………………11

1-5 Kinetic stability of vesicles…………………………………………………………12

1-6 Thermotropic phase behavior of Phospholids…………………………………13

1-7 Permeability of phospholipids membrane………………………………………..16

2. Technical Methods and Materials…………………………………………………...20

2-1 Differential Scanning Calorimetry (DSC)…………………………………………20

2-2 Dynamics Light Scattering (DLS)………………………………………………….23

2-3 Small Angle Neutrons Scattering (SANS)………………………………………..27

2-4 Rheology……………………………..................................................................36

2-5 Stopped Flow………………………………………………………………………..40

2-6 Viscometer…………………………………………………………………………..41

2-7 Materials……………………………………………………………………………..42

3. 1st Part: Admixtures of cosurfactants and copolymers – Effects on size

distribution and thermodynamics………………………………………………………45

3-1 Pure F108 solution………………………………………………………………….47

3-2 Mixtures of apolar oil and F108 solution………………………………………….49

3-2-1 1-Hexanol………………………………………………………………………….49

3-2-2 Geraniol …………………………………………………………………………...60

3-2-3 Toluene…………………………………………………………………………….64

3-2-4 Influence of apolar oil in F108 solution…………………………………………68

3-3 Primary alcohols (Ethanol, 1-Butanol, 1-Hexanol and 1-Octanol)

and F108solution ……………………………………………………………………….71

3-4 Mixtures of polymer and F108 solution…………………………………………..84

3-4-1 Homo copolymer PPO and F108 solution……………………………………..84

3-4-2 Kollicoat MAE 30 DP and F108 solution……………………………………….91

4. 2nd Part: Kinetic stability of Phospholipids and CR3099 vesicles……………….94

4-1 Phospholipids solution……………………………………………………………...94

4-1-1 Phase behaviour………………………………………………………………….94

4-1-2 Phase transition…………………………………………………………………..95

4-1-3 Membrane thickness of the unilamellar vesicles……………………………...97

4-1-4 Stability of the unilamellar vesicles……………………………………………..99

4-1-5 Permeability……………………………………………………………………...103

4-1-6 Conductivity……………………………………………………………………...108

4-2 Diesterquat CR3099 solution…………………………………………………….109

4-2-1 Phase behaviour………………………………………………………………...109

4-2-2 Stability of small vesicles for CR3099 solution………………………………110

4-2-3 Membrane thickness of the unilamellar vesicles………………………........111

4-2-4 Additive and CR3099 solution …………………………………………………113

5. 3rd Part: Gel Phases of multi lamellar vesicles (TDMAO, TTABr and

1-Hexanol)………………………………………………………………………………118

5-1 Phase behaviour…………………………………………………………………..118

5-2 Properties of gel phases………………………………………………………….122

6. Conclusion and outlook…………………………………………………………….129

7. Appendix……………………………………………………………………………..133

8. Acknowledgement…………………………………………………………………..136

9. Literatures……………………………………………………………………………137

10. List of publication…………………………………………………………………..141

1. Introduction

This doctoral dissertation is subdivided into three parts. The first part discusses that

solubilzates are effective in the formation of block copolymer micelles. The second part is

concerned with the investigation into the effect that amphiphilic copolymers have on

vesicle structure and stability. Finally, the last part puts an emphasis on the vesicle gels.

1-1 Thermodynamics and Packing Parameters[1, 2]

Surfactants are composed of hydrophilic head group and hydrophobic chain length. They

can self-assemble in aqueous solutions once a characteristic concentration has been

surpassed. At low concentrations, the surfactants are dissolved as single molecules due

to the large contribution to the free energy from the entropy of mixing, which overcomes

the unfavourable contributions from the hydrocarbon-water contact. At higher

concentrations, i.e. above the critical micellar concentration (cmc), the surfactants form

aggregates in the form of micelles. Some surfactants are also quite thermo-sensitive, e.g.

Pluronics and all surfactants containing ethylene oxide (EO) units in general. Their micelle

formation does not only depend on the concentration, but also on the temperature. Here

the temperature above which micelles are formed is called the critical micellar

temperature (cmt).

The aggregations due to this dual character are self-assemblely in water in a variety of

morphologically different structures [3-7]. The driving force for this aggregation process is

the tendency of the hydrophobic part to minimize its contact with water. An effect, called

the hydrophobic effect, is mainly due to the entropic gain of the water structure by not

being in contact with the hydrophobic part [8]. The shape and structure of surfactant

micelles are determined by the structure and properties of the constituting molecules, their

interactions, and the thermodynamics of the system [9]. A variety of effective shapes

within the micelle are observed from spherical and rod-like micelles to amphiphilic bilayers.

The shapes of micelles depend on the molecular constitution of the amphiphilics and can

be explained by a simple geometric consideration, which is called the packing parameter

model. The packing parameter p is calculated from the ratio of hydrophobic volume (

) to

the optimum head group area (

) and chain length (

). The scheme of the packing

parameter model is presented in Fig.1-1-1 and the equation is expressed as follows:

)/( sss lavp 

(1-1-1)

The packing parameter is able to determine the preferred curvature of aggregates. If p is

less than 1/3, the aggregates form spherical objects. In the first part of this dissertation,

the pluronic F108 is selected to anaylse the formation of micelle phases dependent on

temperature. Cylindrical and rod-like micelles are formed for 1/3 < p < 1/2. If the amounts

of F108 are increased in a solution, then rod-like micelles and other Pluronics like F127

would be observed as well [10, 11]. Bilayer structures are expected for p < 1/2 and

normally they form lamellar phases or vesicles particles in a solution. The DMPC

phospholipids and CR3099 diesterquat surfactants are selected to investigate the vesicles

in the second part. They form large unilamellar vesicles (LUVs) in a vartiety of sizes,

especially phospholipids. The small unilamellar vesicles (SUVs), having only one single

bilayer, are obtained from LUVs by means of extrusion. If the value

is larger than 2,

the reverse structures should be formed. In general, this simple scheme works well for the

explanation of experimentally observed amphiphilic structures.

Fig. 1-1-1: Description of parameters of packing parameter from surfactants

1-2 Solubility capacity based on the Hildebrand parameter [12, 13]

The Hildebrand parameter, as well as the solubility parameter δH, based on a common

solution theory, is proposed by Hildebrand [14]. Traditionally, this parameter δH has been

expressed in (cal/cm3)1/2. It is obtained from the cohesive energy density ρU, which is the

measure of the interactions among the molecules in the condensed phase [14]. The

equation is as follows:

 

2/1





(1-2-1)

The Hildebrand parameter δH is often used to predict miscibility behaviour for medical and

technological applications, such as the prevention of asphalting precipitation, the

estimation of the shelf life of polymers and drug formulations [15-19], the development of

synthetic membranes, and the formation of micelles self-assembly and gelation processes

and nanocomposites [20-23]. Additionally, the correlate polymer properties, such as the

glass transition temperature and the permeability of molecules, can be estimated

accurately by means of the solubility parameter [24]. The Hildebrand parameters are

determined by experiments via the heat of vaporization ΔHv. The equation is, in general,

presented as follows:

 

2/1





























RTH





(1-2-2)

ρ is the density of the solvent, T is the absolution temperature and Mw is the molecule

weight of the solvent. In this experiment, three apolar oils, which are 1-Hexanol, geraniol

and Toluene, are selected as the mixtures at given concentrations of the F108 solution.

Each of the Hildebrand parameters is calculated by equation (1-2-2).

Tab. 1-2-1

Oil

ΔHv /calmol-1

Mw/ gmol-1

ρ/ gcm-3

δH/ (calcm-3)1/2

1-Hexanol

12708.5

102.18

0.816

9.83

Geraniol

14060.7

154.25

0.882

8.77

Toluene

9368.5

92.14

0.862

9.06

PPO

9.34

PEO

10.5 + 0.5

water

23.4

The Hildebrandt parameter of PPO, PEO and water molecules are found from the

publications [25, 26]. If δH values of solvents are closed to each other, they can easily be

homogenous.

1-3 Thermodynamics of micellization [27]

There is an intepretation for the micellization process that is viewed as an energy barrier-

triggered phenomenon [28]. The micelle formation happens as the free enthalpy of the

micelle is lower than that of the unimer’s. The PEO–PPO–PEO copolymers are dissolved

in water as unimers dispersed below their critical micelle temperature (cmt) or

concentration (cmc). Micellization of Pluronics in aqueous solutions is mainly entropy-

driven and can be initiated by increasing the temperature at a fixed concentration. It is

reasonable to assume that the transport phenomena do not play a role in their formation.

The blocks copolymer is sensitive to the concentration alone and temperature of the

solution. The dehydrated process transitions very fast from unimer to micelle phases.

Therefore, the kinetics of the micellization is of no practical interest.

Fig. 1-3-1: Phase transition model of triblocks copolymer from unimers to micelles

Fig. 1-3-1 presents the thermaldynamic process of blocks polymer. When the unimers

translate into micelles, the energy is adsorbed. Forming the micelle phase is the

endothermic reaction. The entropy of micelles is caused by the hydrophobic part of the

copolymer. By adding oil at fixed solution of the copolymer results in an entropy increase

△Hmic

Unimer phases

Micelle phases

Temp. or con.

1-4 Cloud point

The cloud point is defined as when the additive in solution is no longer soluble at critical

conditions, such as temperature or concentration. The phase behaviour of the solution will

not be homogenous. When the solution is not homogenous, it starts to perform a turbid or

diphase solution. For a tailback copolymer solution, the cloud point, also known as the

phase separate temperature, is the temperature at which the solution starts to be

heterogeneous. Two phases appear, thus the solution becomes cloudy. The thermal cloud

point for triblock copolymers is an interesting topic to investigate because they dehydrate

depending on the temperature. Some research on the subject has been published in

recent years [10, 29, 30]. Triblock copolymers contain amphiphlic character and are

sensitive to temperature changes. PO block molecules start to dehydrate with increasing

temperature. EO blocks molecules present more hydrophilic than PO blocks, but EO

blocks can still start to dehydrate at high temperatures. For example, the dehydration

process of F108 happens at 30oC at a weight concentration of 5%. It is caused by PO

blocks. The dehydration process of EO blocks happens at 110oC and can be analysed by

DSC. The entropy for dehydration of EO blocks is lower than the dehydration of PO blocks

[10]. If the EO and PO blocks of F108 are all dehydrated, the solution becomes

heterogeneous.

The cloud points of other triblock copolymers, such as F88, F68, P65 and L62, are all at

higher temperatures in comparison with F108. The low molecule weight of EO blocks

leads to increase the temperature of cloud points [10].

1-5 Kinetic stability of vesicles

This experiment puts emphasis on producing small unilamellar vesicles (SUVs) and

investigating the stability of small uinlamellar vesicles over a long period of time. The

observation time usually takes at least one month, even if the sample appears to be an

instable phenomenon, such as precipitation. It will stop being analysed. The phenomenon

of precipitation is caused by the fusion effect. Each of the individual small vesicles fuses

together in the solution. The large vesicle is formed by small ones. Fig.1-5-1 shows the

mechanism of the fusion process. First, the unfused vesicles have to approach each other.

The grey rhombus is the contact area between the two individual vesicles. Each of the

unfused vesicles tries to approach then adhere to one another. In the adhesive part of two

vesicles, the phospholipids will rearrange by themselves. Two adhesive lipid bilayers will

disappear and the lipids are shifted nearby. After the fully-fused process is completely

finished, two vesicles become one large vesicle. However the fully-fused process is hardly

reversed.

Fig. 1-5-1: Scheme of fusion process

The difference between hemifused and fully-fused vesicles is that fully-fused ones contact

with the inner part of a membrane. Small vesicles combine only with bilayer parts of

membranes when they are in a hemifused process. There are some forces between

vesicles and solvents when they are in the fusion process.

unfused

hemifused

fully fused

Hydration repulsion

Hydration repulsion is caused by the solvent. The strong resulsion appears between

bilayers, which are defined as hydration repulsion. These repulsion forces can be

analysed by means of a surface forces apparatus (SFA). Normally this instrument is used

for measuring forces between surfaces [31, 32]. Hydration repulsion can be explained as

the work required for removing the water molecules around hydrophilic molecules in the

bilayer system [33]. Precisely, the result is that the free energy between hydrophilic

surfaces requires the modification of the H-bonding network of liquid water in the vicinity

of polar and H-bonding surface groups.

Hydrophobic attraction

When small unilamellar vesicles approach each other successfully in the fusion process,

the attraction of hydrophobic is enhanced. This phenomenon, known as the hydrophobic

effect, is the driving force for the self-assembling of lipids into aggregates, such as bilayer

membranes and other structures [34].

Van der waals forces[34, 35]

These forces are attractive due to the dipole-dipole interaction between bilayers. The

dipole-dipole interaction includes permanent and induced dipoles. While vesicles are

closed, a separable hydration interaction between them reduces with an exponential

decay.

1-6 Thermotropic phase behavior of Phospholids [36]

Phospholipids as well as triblock copolymers are sensitive to temperature. The sequence

of thermotropic transitions of hydrated phospholipids can be generally represented by the

following scheme:

cMHQLPLL lt

s





Fig. 1-6-1: Phase transition of phospholipid

The symbol Lc is called the crystalline phase, in which the phospholipids are not hydrated.

When Lc turns to Lβ at temperature Ts. Lβ is the hydrated lamellar gel phase and Lα is the

fluid lamellar phase. With increasing temperatures, the main phase transition process

observed by Nano DSC occurs from Lβ to Lα. The main phase transition happens at Tt.

Below Tt, the pretransition from a low-temperature gel phase to an intermediate ripple

phase (Pβ’) occurs at Tp. When the temperature keeps increasing, the fluid phase

undergoes further transitions, first transforming into an inverted cubic phase (QH) and then

an inverted hexagonal phase (HH). The final stage is the transition into the inverted

micellar phase (MH) that occurs at temperature Tl. This phase is characterized as

immiscible oil in excess water. Not all the phases and transitions mentioned above appear

for a single phospholipids [112].

Phase Lα is characterized by disordered lipid chains. The main phase transition from Lβ to

Lα is explained as Trans-Gauche Isomerization. Microscopic chain melting is connected

with rotation around the carbon bonds of phospholipid hydrocarbon chains. The lowest

energy holds for trans and highest for cis conformations of the chains. In the gel state, the

rotation is restricted and the saturated chains are in the all-trans conformation. When the

temperature approaches the phase transition region, it increases the probability of rotation.

Rotation by 120o relative to trans conformation results in the formation of gauche (+) or

gauche (-) conformations.

Fig. 1-6-2: Conformation of the hydrocarbon chain of a DMPC. A – trans configuration, B –

gauche-trans-gauche conformation

Energetically, the gauche conformation does not differ substantially from the trans

conformation (2–3 kJ mol-1). However, these two conformations are separated by a

relatively high energetic barrier (12–17 kJ mol-1). The appearance of the gauche (+)

0.127 nm

0.15 nm

conformation causes stereo-dimensional difficulties in a bilayer. However, the subsequent

gauche (-) rotation results in a diminishing sterical repulsion. As a result of the gauche

(+)–gauche (-) rotation, a kink conformation appears in the lipid chain (see Fig. 1-6-2). In

this case, the spatial configuration of the chain is preserved, but the chain is 0.127 nm

shorter and the cross-sectional area increases. The phase transition in a lipid bilayer from

a gel to a liquid state is therefore accompanied by a decrease in the thickness and an

increase in the area per molecule. The energetic barrier,

E

equal to

H

, can be

determined by Nano DSC. With the following equation:



























RT

vexp

(1-6-1)

is the frequency of torsional oscillations as the unit of s-1.

The gauche conformation appears with a high frequency due to torsional oscillations.

is obtained from eq. 1-6-1 when the enegetic barrier is found.

1-7 Permeability of phospholipids membrane [36, 37]

The biological membrane is one of the most important cell structures. It represents a city

gate for the cell with a barrier function that provides directional transport of species into

the cell, and waste and toxic compounds are pushed out of the cell. In addition, the low

permeability of the membrane for charged particles, e.g. ions, allows a non-equilibrium ion

distribution between the extracellular and cytoplasmic sides of the cell, which is crucial for

cell function. Phospholipids are the most common lipids in cell membranes. A

phospholipid bilayer membrane represents a self-assembled structure in an aqueous

solution. This is the result of the hydrophobic effect, whereby the non-polar acyl chains of

lipids (which form the interior of the bilayer) and the non-polar amino acid residues in

proteins tend to be squeezed out from the aqueous phase. In this dissertation,

determining the permeability of small unilamellar is presented. The kinetic reaction

through the membrane takes place with the help of FeSCN2+ and F- ions analysed by

Stopped Flow.

Fig. 1-7-1: Model for the diffusion of ions for 0.1% DMPC extruded solution: (I.) Diffusion of

FeSCN2+ to outside of the vesicles, (II.) Diffusion of F- to the inside of the vesicles

The reaction between FeSCN2+ and F- leads to colourless, stable fluoride complexes, and

is used to measure the permeability of vesicles:

  SCNFeFFFeSCN 22

(1-7-1)

FeSCN2+

(I.)

(II.)

F-

While the rate constants for the formation of the red complexes between ferric and

thiocyanate ions, mainly FeSCN2+ and Fe(SCN)2+ [38], and the reactions between Fe3+

and F- ions [39] [40] have been determined by kinetic measurements, no results seem to

be available in the research that has been done on the reaction between FeSCN2+ and F-.

The known rate and equilibrium constants in the reaction scheme are given in Tab.1-7-1.





 23 1

FeSCNSCNFe k

(1-7-2)

 







 2

SCNFeSCNFeSCN k

(1-7-3)





 23 1

FeFFFe k

(1-7-4)





 2

FeFFFeF k

(1-7-5)

FeFFFeF k

k

 

(1-7-6)

The constants in Tab.1-7-1 show that the stability of the fluoride complexes is 100 to 1000

times larger than the stability of iron thiocyanate complexes.

Tab. 1-7-1: Constants of the fluoride complexe [38],[4]and [5]

Contants/ L．mol-1

SCN-

F-

150

105

104

103

This simple geometric model gives a calculated aggregation number for large unilamellar

vesicles of the measured size. The membrane volumen of one unilamellar vesicle is

approximately given by

dRV 2





(1-7-7)

And

wagg





(1-7-8)

Equation (1-7-7) and (1-7-8) giving the aggregation number

agg M

NdR





(1-7-9)

where R is the radius of unillamellar vesicles, d is the thickness of membrane, ρ is the

density of phospholipids, NA is Avogadro’s number, and Mw is the molecular weight of the

phospholipids.

Fick’s first law of diffusion

The diffusion of the FeSCN2+ complex and the F- ion can also be discussed by Fick’s first

law of diffusion; the equation is given as follow:

KDS

dn 

. (1-7-10)

From the inside membrane of FeSCN2+, the rate diffusion of FeSCN2+ is driven out of the

vesicles

 







 2

SCNFe

SCNFe c



, (1-7-11)

where n is the number of Fe(SCN)2+ complexes per vesicle, S is the membrane surface of

one vesicle as the unit of m2, V is the volume of one vesicle as the unit of m3,



is the

thickness of membrane as the unit of m, D is the diffusion coefficient for the diffusion in

the membrane as the unit of m2s-1, K is the partition coefficient of ions between water and

hydrocarbon phases, as well as lipids bilayer phase, and △c is the difference of

concentrations outside and inside the vesicles.

In the model Fig. 1-7-1, the ferric complex should decay as a first-order process with the

rate constant kexp given by



k



exp

(1-7-12)

The above expression could be further simplified if a permeability coefficient P is defined:



P



(1-7-13)

Combined with equation (1-7-12) the rate constant kexp is then given by

exp 







, (1-7-14)

where R is the vesicle radius as unit of cm, P is the permeability coefficient as unit of

cm‧s-1 and kexp is the first-order rate constant as unit of s-1



exp k

, (1-7-15)

where



is the relaxation time as unit of s.

2 Technical Method and Materials

In the following, techniques used to characterize micellization, vesicles and gel phases

are discussed. These include methods for analysing thermaldynamical properties and

permeabilities, as well as classical methods for studying hydrodynamic radius Rh of

unimers, micelles and vesicles. Characterization methods for rheology and viscosity are

also introduced. Moreover the preparation of samples is put into this part.

2-1 Differential Scanning Calorimetry(DSC)[41]

Differential scanning calorimetry is a useful tool for analysing the thermal properties of

materials. The phase transition of Pluronics and phospholipids are sensitive to

temperature, so that they are suitable to be investigated by this instrument. The

thermaldynamical reaction is observed when DSC scans as a function of temperature.

The basic theory of DSC relates to heat capacity

. The heat capacity Cp is measurable

in physical quantity and defines the amount of heat required to increase the temperature

of the sample by 1 degree Kelvin or Celsius. Thus,

Cp



(2-1-1)



T is the change in temperature and

is the amount of Heat required to achieve

T

The heat capacity relates to the energy, which accompany endothermic and exothermic

reaction. So the equation can be written as

p





















(2-1-2)

Under the constant pressure condition, the required Heat Q is equal to the enthalpy △H.

Fig. 2-1-1: DSC scan as function of temperature [41]

Fig. 2-1-1 provides the information to analyse the phase transition of samples, such as Tm,

△Hf, Tc, △Hc and Tg. The parameter Tm is defined as the melting point of temperature and

is read at the top of the endothermic peak. △Hf is the amount of energy that the sample

absorbs while melting. The term Tc is called the crystallisation point and is read at the top

of the exothermic peak. The enthalpy of △Hc is the amount of energy which the sample

releases while crystallizing. In the part of the amphiphlic triblock copolymer the transition

peak is marked as Tpeak instead of Tm and Tc. The entropy of Pluronics is written as △H(PO)

for both process instead of △Hf and △Hc , because the phase transition happens as a

result of the dehydration of each PO block. The parameter Tg is called the glass-transition

temperature. It happens when an amorphous polymer or an amorphous part of a

crystalline polymer goes from a hard, brittle state to a soft, rubbery state. This experiment

puts no emphasis on discussing the Tg point of triblock copolymers and phospholipids. The

Fig. 2-1-1 shows an arrow that points to the occurrence of thermal degradation of the

polymer and the maximal temperature of thermalstability is determined. There is another

arrow, which is called Tonset. It is read at the beginning of the thermal peaks. After

measuring the samples, they were analysed by Nano Analyze software to determine the

temperature and enthalpy. The Nano Analyze software and Nano DSC instrument were

developed by the company TA Instrument.

The triblock copolymer F108 is sensitive about temperature and concentration. At a fixed

concentration of F108, the critical micelle temperature (cmt) is analysed by means of DSC.

The endothermic peak occurs when the PO blocks that are part of F108 become

hydrophobic. The PO blocks acquire more hydrophobic features when temperature

increases, accompanied by energy absorbtion. Normally, the PO blocks with hydrophobic

exo

↗

Tonset

properties are hard to dissolve in aqueous solutions. Because they bond covalently with

long chains of EO blocks, the phase behaviour appears homogeneously still in water,

even if the sample is already over the cmt. Conversely, in the cooling process, PO blocks

regain their hydrophilic character and the exothermic peak is cause by energy release.

The phase transition of Phospholipids is observed by the Nano DSC instrument as well.

The arrangement structure of phospholipids is sensitive to temperature. It turns from

crystalline phases Lc to the fluid lamellar phase Lα when the temperature increases.

Set-up of instrument

In general, the set-up of the DSC instrument consists of pans and sources of heating and

cooling. The Fig. 2-1-1 shows a simply sketched set-up of DSC. The measuring sample is

put in pan S only. Pan R keeps empty usually. The furnace provides a stable continuous

heat flux to both pans. Furnace system provides uninterrupted heats and leads

temperature increasingly. Heats are accepted by both pans. The accepted heats cause

changes in the differential power supplied to the sample if the energy is adsorbed or

released.

Fig. 2-1-1: Sketch set-up of the DSC instrument

There are two kinds of furnaces for DSC instruments. One is like the one shown in Fig. 2-

1-1 and is called Heat flux DSC. The sample and reference materials utilize a single

furnace and heat flows into both samples via an electronically heated constantan

thermoelectric disk [42]. There is another type of DSC, which is called power-

compensated DSC. It has two individual furnaces for samples and references respectively.

The Nano DSC instrument is used in this experiment and it is of the Heat flux DSC type.

furnace

Heat flux

The shape of cell container has a special design, made as capillary cells for sample and

reference materials (see Fig. 2-1-2).

Fig. 2-1-2: Picture of capillary cells

The Nano DSC instrument was designed by the TA instrument company. This instrument

has a very high sensitivity and is suitable for analysing the diluted solution of bio

molecules like phospholipids liposomes molecules. Capillary cells are one of the

advantages. The contact area of capillary cells is larger than pan cells. It creates a stable

post-transition baseline and it enables complete and accurate determinations of transition

temperatures (Tm) and enthalpy (ΔH).

2-2 Dynamic Light Scattering (DLS) [43]

The size and the distribution of micelle phases and vesicles in the aqueous solution is

analysed by the dynamics light scattering method. The basic theory of light scattering is

that the light from a laser passes through a polarizer to define the polarization of the

incident beam and then impinges on the scattering medium. The scattered light then

passes through an analyser which selects a given polarization and finally enters a detector.

The position of the detector defines the scattering angle θ. The intersection between the

incident beam and the scattered beam is defined as a volume V, called the scattering

volume or the illuminated volume.

Fig. 2-2-1: Simple sketch of scattering geometry

The big blank is the illuminated volume V and the total radiated field at the detector is the

superposition of the fields radiated from all infinitesimal volumes d3r at positions r, with

d3r

Detector

rR

respect to the center of V. The detector is at position R with respect to the center of the

illuminated volume.

The molecules in the illuminated region are perpetually translating, rotating and vibrating

by virtue of thermal interactions. Because of this motion, the positions of the charges are

constantly changing so that the total scattered electric field at the detector will fluctuate in

time. Thermal molecular motion is erratic, so that the total scattered field varies randomly

at the detector. The vector

is defined in terms of the scattering geometry as

fi kkq 

(2-2-1)

where ki and kf point respectively, in the directions of propagation of the incident wave and

the wave that reaches the detector. The angle between ki and kf is called the scattering

angle θ. The magnitudes of ki and kf are, respectively, 2πn/λi and 2πn/λf, where λi and λf

are the wavelengths in vacuo of the incident and scattered radiation, and

is the

refractive index of the scattering medium. It is usually the case that the wavelength of the

incident light is changed very little in the scattering process so that

fi kk 

(2-2-2)

Thus the triangle in Fig. 2-2-2 is an isosceles triangle and the extent q can be found from

the law of cosines,

sin4cos222 222222



iiifiifif kkkkkkkkkq 

(2-2-3)

sin

sin2







kq 

(2-2-4)

This is the Bragg condition. It specifies the wave vector component of the dielectric

constant fluctuation that will give rise to scattering at an angle θ.

Fig. 2-2-2: Description of the scattering vector q

All samples were measured by this type of ALV/CGS-3 Compact Goniometer System with

a He-Ne-laser at wavelength of 632.8 nm. The detecting angle was always at 90o, so the

values of the scattering vector are the same in this experiment. The temperature of the

medium is controlled normally at 25oC, while some pluronis samples are measured from

15 to 40oC. The measured samples were analysed with the software of ALV – 7004

version 3.0.

Analysis of DLS measurements

The scattered intensity is measured in Hz as a function of time and it fluctuates up and

down dynamically with time. The particles moves as Brownian motion in a solution and it

results in unstable scattering intensity. Those irregular fluctuations can be interpreted by

autocorrelation functions. It is a mathematical tool used to describe the random process in

statistics. In general, the function is written as

     



TttItIdttC



(2-2-5)

It describes the status of particles at the moment when t=0 second and the next moment

at δt seconds. Deciding the measuring time of the sample is dependent on the particle

size and the viscosity of the solvent, and it can be set from seconds to hours. The

scattering intensity results in the relative distance of the position between particle and

detector. It relates to the diffusion movements of particles in solutions. The particle

diffuses dependent on time. When t is from 0 to 1 sec., the volume of the particle including

diffusion area increases; it results in a high-intensity correlation function. If the particle is

observed from 0 sec to a period of time, it still diffuses with time. However, the volume of

Analyser

Detector

Polarizer

fi kkq 

diffusion is limited because movements of the particle are similar and repeated with high

probability. The correlation function intensity decreases when time is lengthening.

Therefore, the autocorrelation function of DLS is time-dependent.

1E-5 1E-4 1E-3 0,01 0,1 1 10 100 100010000

0,0

0,1

0,2

0,3

g2-1

/ms

Temp./ oC

3,6mm F108 solution

Fig.2-2-3: Autocorrelation function of 3.6 mm F108 measured with different temperatures

The analysis of the cumulant expansion of the correlation function is performed by fitting a

polynom up to third order to the function ln(g2(t)-1). The polynomial coefficients are

converted into the coefficients of the cumulant expansion of the field correlation function

 

lnln t

tAtg 

(2-2-6)

Amplitude (A),



(1/Gamma), u2, u3, are the parameters of this correlation function. The

unit is in milliseconds (ms) and the unit of u2 and u3 are therefore 1/ms2 and 1/ms3. In this

part takes the first order of parameter



to determine the hydrodynamic radius Rh.

Rh





(2-2-7)

The value η is the viscosity of the measuring medium and in this case is water. It

decreases with increasing temperature and q is scattering vector dependent on scattering

angle and wavelength (see eq 2-2-4). When the ALV-7004 is used for analysing DLS

measurements, step of simple fit will be selscted. Simple fit is a model of cumulant fit to

calculate the correlation function. After calculation of simple fit the width and polydispersity

index (PD. I) of the sample is obtained. The equations of width and PD.I are as follows:

Width 

2

(2-2-8)

.

u

IPD

(2-2-9)

The other method for analysing the autocorrelation function, called the ALV-Regularized fit

step. The decay time is taken from 0.001 to 100 ms into consideration. DLS-Exponential

g2-1(t) is used as a nonlinear fit model (see eq. 2-2-10) and the size distribution is

displayed as a function of the radius as a unit of nm and unweighted log.

   

2max

min

1











 



 dGetg t

(2-2-10)

In this experiment, the results of PD.I (Eq. 2-2-9) are calculated from a second and

parameter of u2 at eq. 2-2-6. It is a standard to determine the size distribution of particles

in solutions. The low value of PD.I appears in the size distribution of particles more

homogenously in solutions.

2-3 Small angle neutron scattering (SANS)[2, 44, 45]

One of the most suitable methods for obtaining information on the structure and

interactions of micelles is by means of neutron scattering. This technique is called small

angle neutron scattering, which is similar to other scattering methods, like DLS and SAXS.

They are complementary to investigate the shape, size, distribution for colloid systems

and soft matter. Neutrons are used for the technique SANS as scattering radiation. The

specialty of neutrons has no charge and neutrons interact with atoms via nuclear rather

than electrical forces, and nuclear forces are very short-range of the order of a few fermis

(1 fermi = 10-15 meter). Furthermore, the wavelength of neutrons is in the range of 0.1 to

1 nm and the energy is approximately 1 to 100 eV. An important feature of neutron

scattering is the high incoherent scattering cross-section of hydrogen. However hydrogen

molecules appear low incoherent scattering cross section by measuring of X-ray

scattering like SAXS because of the electron density.

Samples preparation and instrument set-up

Neutron scattering is the difference in the scattering length between hydrogen and

deuterium, which is important for the variation of the contrast between the particles and

the matrix. So the samples are prepared normally in D2O additionally. Considering that the

density of D2O is 1.1 times heavier than H2O, the samples would be weighted 1.1 times

heavier in order to equal the molar concentration of aqueous samples. The SANS

measurements are usually prepared in D2O solvents in order to enhance the contrast and

reduces the incoherent background from scattering from hydrogen in the sample. Block

copolymer micelles and microemulsions are analysed with the solvents D2O and H2O.

The contrast and scattering length density is varied by changing the D2O/H20

concentration of the solvent. Those aggregates with various parts from each sample in

solution can be can be highlighted in different mixtures of deuterated and hydrogenated

solvents.

The software SASfit is used to analyse the measuring SANS curves. It is developed at the

Paul Scherrer institute (PSI) in Switzerland and is written for analysing and plotting small

angle scattering data [45]. Other important information, like gyration radius, scattering

invariant and porod constants, can be obtained by SASfit. There are lots of models of form

factors and structure factors to be selected to fit size distribution together.

Fig. 2-3-1: The principle of a flexible steady-state SANS setup pictured by J.S. Pederson [2]

The most of the samples under the group of Prof. M. Gradzielski were measured at the

ILL in Grenoble, France. There were same samples measured at the HZB in Berlin,

Germany. The Fig. 2-3-1 shows the primary principle SANS setup for the steady-state

type. It is one type of neutron source for SANS instruments. The steady-state means that

the reactor is continuously produced by the fission processes. The other type, called a

spallation source, provides a pulsed neutron beam. The range of available scattering

vectors is typically from about 1 0-3 to 0.5 A- I, which typically requires the use of three

different sample-detector distances and neutron wavelengths. A particularly broad range

of scattering vectors, from 1 0-3 to 1 .5 A- I, is covered by the D22 instrument at ILL in

Grenoble, France. The principle of the set-ups is shown in Fig. 2-3-1. Part (a): The

smallest q values are reached with the longest sample-detector distance, with a long

collimation and neutron wavelength. Part (b): The largest q values are reached with the

detector as closely to the sample as possible and a short neutron wavelength. The

sample-detector distance can be varied and the divergence of the incident beam can be

chosen to match the angular range covered by the detector. This is done by varying the

distance from the source pinhole to the sample. Neutron guides are inserted in front of the

source pinhole in order to prevent a loss of intensity. For all these instruments, a

mechanical velocity selector is used for monochromatizing the neutrons. The smallest q

values are reached with the longest sample-detector distance for which the collimation is

chosen. The wavelength is as long as practically possible. The largest q values are

reached with the detector as close to the sample as possible and with the shortest

possible wavelength. The flux at the sample position depends strongly on the wavelength

and the collimation. The flux is typically about 107 neutrons per second at the sample

position for short wavelengths around 3 Å. For longer wavelengths around 15 to 20 Å) and

long collimation distances ( > 5 m), the flux is several orders of magnitude lower. Useful

measurements can be done with a flux as low as 103 neutrons per second, but with long

acquisition times from 4 to 12 hours. For example with the D11 instrument at ILL (Ibel, 1

976), the length of the collimator can be varied from 2.5 to 40.5 m, and the sample-to-

detector distance can be varied in the same range. The velocity selector provides a

wavelength resolution of 9% and wavelength in the range from 2 to 20 A. For D22 at the

ILL, the source, the neutron guide and the geometry have been optimized to provide a

very intense incident flux. The length of instruments collimation and flight path is 7.6 and

18 m, respectively. With a large area-sensitive detector (1.0×1.0 m2) which can be offset,

a very broad range of scattering vectors can be covered in a single setting.

The primary theory of small angle neutron scattering

The scattering intensity, I(q), from a solution composed of particles, can be expressed in

terms of a form factor, P(q), and a structure factor, S(q), where q is the scattering vector

(q), which is defined as the difference between the vectors of the scattered and incoming

neutrons. The equation is given by













2

sin







(2-3-1)

The form factor P(q) reveals the geometric characteristics of the single aggregate in

solution, and the structure factor S(q) accounts for correlations due to inter-particle

interactions. The form factor and the structure factor are assumed to be independent, and

the scattering intensity for spherical, monodisperse particles in the differential cross

section, which is from the articles by Grillo, Narayanan and Das and Doniach [46-48] can

be expressed as

       

qSqPNq

qI 







(2-3-2)

N is the number density of the scattering particle and q is the scattering vector. P(q) is the

particle form factor related to the structure of the particles and is the scattering amplitude.

   

qAqP 

and

   

RqVqA 



(2-3-3)

In this expression

     

 

cossin3

xxx

x



(2-3-4)

and





is the difference in scattering length between the surfactant and solvent, V is the

particle volume and R is the particle radius.





can be determined by the equation as

follows:

solvsurf





(2-3-5)

Where ρsurf is the scattering length density (SLD) of the surfactant and ρsolv is that of the

solvent. These can be calculated from the apparent specific density, which means the

effective density of the molecule in the solution, when the changes in the water in the

vicinity of the molecules are also ascribed to the molecule, of the surfactant and the

density of the solvent. They are calculated as the sum of all scattering lengths of the

molecule, divided by the effective volume of the molecule calculated from the density.

Since the densities and apparent specific densities can be determined accurately [49-51],

it is also possible to obtain accurate values for the scattering length densities. The

equations in eq. 2-3-2 to 2-3-4 can be reduced by relating V to the radius as V = (4π/3)R3,

and the number density N to the concentration of the solution c (mass per volume)

corrected for the inter-micellar concentration c0 as N = (c – c0)/(Nagg Msurf), where Msurf is

the mass of a surfactant molecule, and Nagg is the aggregation number calculated as Nagg

= V/Vsurf, where Vsurf is the volume of a surfactant molecule calculated from the apparent

specific density. With this, the only fit parameter of the model is the radius R of the

micelles. The inter-micellar concentration c0 is in a practice set equal to the cmc, which

can be estimated independently, for example, by surface tension measurements. The

above considerations show, to give a very simple example, the strength of including

molecular constraints in the analysis [52].

Fig. 2-3-2: SANS data of hexadecyltrimethylammonium chloride (HTAC or CTAC) micelles in

D2O without added salt [53]

This dissertation presents most of the SANS measurements as being from the triblock

copolymer F108 with an addition of 1-Hexanol. The block copolymer model for

aggregation process can be organized into three groups for analysing the behavior of

micelles phases in solutions with suitable form factors. The model of background Gauss

and Spherical shell i in the experiment is selected for the form factor P(q) to analyse the

pluronic samples by SASfit program. Analysis of scattering data is expressed as a sum of

two contributions.

 

inccoh IqIqI )(

(2-3-6)

Icoh is the coherent scattering dependent on the shape, size and repartition of domains in

the sample. Iinc is a background because somtimes incoherent scattering is caused by

atomes in particular hydrogen. The value of Iinc keeps normally constant. For a single

population of monodisperse the coherent part of Icon can be expressed as follows:

)()()( 22 qSqPSLDVNqIcoh 

(2-3-7)

with the volumen fraction ψ=N．V. The formfactor P(q) is normalized. V is the average

volumen and N is the number density. △SLD is the average contrast.

The model of Gauss is an interpretation of a polymer chain to explain the phenomenon of

an isotropic random walk in solution. Considering a flexible copolymer coils and each

unimer locates at a distance Rm, its scattering field amplitude is given by

 







N

tiqRm

etqF

(2-3-8)

The scattering intensity averaged over all molecule configurations reads

 





RRiq nm

eqF

(2-3-9)

The unimer copolymers Rm - Rn -distributed if the micelle phases are not

formed completely. The averages〈….〉can be written as

   

6nm

nm RR

RRiq ee 

 

(2-3-10a)



6nm

e



(2-3-10b)

Here b is the statistical segment length and L is the contour length, which equals L = Nb.

The average of the segment inter-distances squares is kept in general for

 



2nmbRR nm 

(2-3-11)

Symbolν parameter from the Flory mean field theory of polymer

solutions [54, 55]. The radius of gyration Rg is given by

 

 N

nm nmg RR

(2-3-12a)

 N

nmb



(2-3-12b)











 N

(2-3-12c)

  





2212 N





(2-3-12d)

Using the general identity

 

   

 





kykNNjiy

, 1

(2-3-13)

The form factor reads

     



















 







11 k

ekNN

(2-3-14)

Going to the continuous limit (N＞＞1), one obtains:

   







exdxqP

(2-3-15a)









UUUU 

























































(2-3-15b)

With the modified variable

  

2212

222 g

Nbq

U





(2-3-16)

SASfit has implemented the generalized Gaussian coil and the standard Debye formula

Gauss. In both cases three versions are implemented which only differ in their

parametrization of the scattering intensity. Flexible copolymer chains are not self-avoiding

and obey Gaussian statistics. Debye (1947) has calculated the form factor of such chains:

 

1exp

IIGauss





(2-3-17)

22 g

Rqu 

(2-3-18)

Rg is gyration radius and I0 is the scattering intensity when q=0.

The other form factor for Spherical Shell i describes when the micelle phases have been

formed. It is obtained by

      

 

2121 1,,,,,,, muRqKRqKmuRRqIShell 



(2-3-19)

   

3cossin

,, qR

qRqRqR

RRqK 





(2-3-20)

If scattering intensity for q = 0, the equation is given by

   

 

121

,,,,lim 











muRRmuRRqIShelli



(2-3-21)

R1 is the overall radius of spherical shell and R2 the core radius. The input parameter △η

is the difference of scattering length density between shell and solvent, which is △η=

SLDshell- SLDsolv. The other input parameter mu is the difference of scattering length

density between core and solvent, relative to the shell contrast, mu= SLDcore-SLDsolvent. Fig.

2-3-3 presents a simple sketch.

Fig. 2-3-3: Schematic diagram of spherical shell i

For each scattering object i next to a size distribution Ni(x; li), a structure factor Si (q; si)

can also be included. When a structure factor is included, there are several theoretical

ways to account for it. The structure factor S(q) can be calculated in various

approximations, like the monodisperse approximation, decoupling approach, local

monodisperse approximation, partial structure factor and scaling approximation of partial

structure factors [45]. At the moment, it is assumed that there are no interactions between

different species of scatterers so that the total scattering is given by the sum of the

scattering of the individual species

   











(2-3-22)

whereby

 





is the species of the differential scattering cross sections. The structure

factor S(q) with hard sphere interaction potential U(r) is limited in the range when

 

rU

for 0 ＜ r ＜ σ (2-3-23a)

 

0rU

for r ﹥σ (2-3-23b)

The symbol σ is LogNormal distribution which is defined with reference to the normal

distribution. A random variable is Log normally distributed if the logarithm of the random

variable is normally distributed. The structure factor with hard sphere is obtained by

   

qRfG

fRqS

HSp

pHSHS ,

241





(2-3-24)

Where

Δη

muΔη

 

   

 

324

6sin6cos634cos

2cos2sin2cossin

AAAAAAA

AAAA

AAA

















(2-3-25)

The symbol α, β, γ and A is the eaquations as follows:

 









(2-3-26a)

 

f

















(2-3-26b)







p

(2-3-26c)

qRA HS

2

(2-3-26d)

The symbol RHS is a hard sphere radius and fp is the different volumen fraction for a hard

sphere interaction potential.

2-4 Rheology [56]

The word “Rheology” comes from Greek originally. The meaning of rheo is the river,

flowing and streaming. Scientifically speaking, rheology is the deformation and flow and

can also be called flow science. There has been some information obtained by means of

rheology experiments, such as the flow behaviour of liquids and the deformation

behaviour of solids. Both connect a large deformation, which is produced by sheer forces

and it occurs the materials to flow. The two plates model is used in this experiment to

analyse the gel phases of multilamellar vesicles. The upper plate with the shear area A is

set by the motion of shear force F and the result of the velocity v can be measured. The

lower plate is stationary and it means v=0. The symbol h is the distance between upper

and lower plates and the measured sample is sheared in this shear gap. In order to make

the calculation of rheometer parameters accurate, there are shear conditions to follow:

1 the sample adheres to both plates and does not slide and slip along them

2 it obeys lamellar flow conditions, in other words, it flows in the form of layers.

Therefore, neither turbulent flow nor vortices occurs.

Fig. 2-4-1: The model of shear test

The shear stress τ defined a





(2-4-1)

F is the shear force as the unit of N, 1N = 1 kgm/s2 and A is the shear area as the unit of

m2. The unit of shear stress τ is Pa. 1Pa = 1 N/m2 = 1 kg/ms2 and the symbol σ is used for

yield stress[57]. The shear strain γ is defined as

X





tan

(2-4-2)

, the ΔX is a movement of route of sample. The definition of shear rate ŕ

V=0

△X





(2-4-3)

The velocity is v as unit of m/s and h is the distance as unit of m between two gaps

Therefore the unit of shear rate is s-1, which can be called reciprocal seconds. The term of

viscosity here means shear viscosity. There is another term of complex viscosity

determined by oscillation test. Sometimes they use the same symbol η. The definition of

shear viscosity is at the equation as follows:









(2-4-4)

The value is the ratio of shear stress τ to the corresponding of shear rate ŕ as the unit of

Pas.

Experimental set-up

There are two different set-ups of rheometers, either equipped with a single head or with

separated heads. The type of separated heads means the motor and transducer are

separated. They are mounted on a different side of measuring geometry. It leads to motor

and torque sensor being decoupled. The other type of single head means the motor and

transducer are mounted in a combined system on the same side. It is used in this

experiment and the sketch is presented in figure.

Fig. 2-4-2: Set-up of rehometer for single head type

The Fig. 2-4-2 shows the ususal set-up of an oscillatory rheometer. The part torque

relates to shear stress τ. When using the controlled shear stress, the electronic

controller sends the appropriate operating current I to the motor which produces the

corresponding torque. A breaking or restoring torque caused by the sample is acting

against the motor torque. Be is the bearing, controlling and verifying the distance of gap

size. PS is the position sensor and relates to the shear rate and deformation. It controls

the rotational speed with angular displacement. The upper plate is selective and

dependent on the characteristic measuring materials.

Fig. 2-4-3: The sketch of four measuring systems commonly using rheometers

Some differerent measurements systems are shown above: From left to right there is a

coaxial cylinder in coquette flow, coaxial cone and plate, coaxial parallel plate, and a

rectangular torsion (see Fig. 2-4-3). It depends how viscose the sample is, normally the

Inductive Motor

Torque

Gap size

Fixed plate

upper plate

type of the coaxial cylinder in a coquette flow are very low-viscose solvent mediums, such

as decane, whose viscosity is 920 uPas at 20oC. The coaxial cone and plate are used for

very low to high viscose liquid and parallel plate is for low viscose liquid to soft viscose

solids. The geometry of rectangular torsion is suitable for soft to rigid solids, like steel.

Each of them overlaps partially. There are some important terms, like G’, G’’ and η*, when

the amplitude sweep and oscillator sweep are measured. G’ is the elastic modulus as the

unit in [Pa] and G’’ calls viscous modulus in [Pa], which relate to complex modulus G*. In

general

strain

stress

G



(2-4-5)

G* is the overall resistance to deformation for measuring materials. However the symbol

change to G0 and is called a shear modulus in some publications [1]. The relationship of

G*, G’ and G’’ can be written as

'''

*iGGG 

(2-4-6)

The elastic modulus G’ means measuring the elastic properties of materials and

investigating how materials store energy so it can be called as storage modulus. The

viscous modulus G’’ denotes the ability of materials to dissipate energy. It analyses the

lost energy as heat and can be called a lost modulus. The parameter η* is the complex

viscosity in [Pas].

2-5 Stopped Flow

Stopped Flow is the most frequently used technique to investigate the chemical kinetic

reaction and movement in solutions. The precision of kinetic measuring time reaches

microsecond (μs).

Experimental set-up

Fig.2-5-1: Schematic diagram of Stopped Flow instrument

The instrument employed was a Bio-Logic SFM400/S. The main part of the Stopped Flow

contains four syringes (S1-S4), a BB Mixer and an HDS mixer. The light can be selected

at suitable wavelengths; in this experiment it is at 450 nm. The BB mixer is the standard

Berger ball mixer; the HDS mixer is a high density mixer. The Syringes S1 and S2 share

the one mixer and S3 and S4 are with their mixer on their own, so the measuring sample,

like FeSCN2+ with DMPC vesicle solution, was put into S4 and the NaF solution in S3.

Light

Absorbance

Cell

BB Mixer

HDS mixer

Exit for mixed solution

2-6 Viscosity

The ubbelohde viscometer, a product made by the SCHOTT SCHOTT GERÄTE Company,

is used to determine the viscosities of CR3099 and F108 solutions. Different types of

capillaries are used for different adhesive level of samples. Capillary Ic, whose range of

viscosity is from 3 to 30 mm2s-1, is used for the F108 solution compatibly. Another capillary

0a is selected for CR3099 solution that the viscosity range is from 0.8 to 9 mm2s-1.

Description of ubbelohde viscometer

Fig. 2-6-1: Schematic diagram of the basic ubbelohde viscometer

After measuring the efflux time of samples from M1 to M2, the viscosity is obtained through

the calculation. The equation is given as follows

 



 tKv

(2-6-1)

It is called kinematic viscosity in cSt (mm2/s), because it takes the ratio of the inertial force

to the viscous force into consideration. The symbol t is the average flow time in sec and

for absolute measurements, the corrected efflux time multiplied by the constant K printed

on each viscometer. The symbol



is correction seconds dependent of flow time and the

type number of capillary for viscometer.

The ubbelohde viscometer is basically

consists of the three tube sections (1, 2

and 3), the working capillary (7) with the

timing bulb (8) and the upper (9) and

lower (5) reservoir. M1 and M2 are timing

marks. They are defined as the flow-

through volumen of the sample and the

mean hydrostatic head is h.

2-7 Preparations of Materials

1st part: Pluronics F108

Triblock copolymer F108 is used without any purification to be dissolved directly in water.

In this experiment, two kins of fixed solution (3.6 mm and 7.0 mm) are prepared for the

parent solution. Tab. 2-7-1 summarizes the the structural formula and molecular weight for

triblock copolymers.

Tab. 2-7-1: Pluronics

Name

Structural formula

Mw[g．mol-1]

Company

F108

[CH2CH2O]132[CH3CHCH2O]50[CH2CH2O]132

14600

BASF

L35

[CH2CH2O]11[CH3CHCH2O]16[CH2CH2O]11

1900

BASF

10R5

[CH3CHCH2O]16[CH2CH2O]11[CH3CHCH2O]16

1950

BASF

The additive selected to be dissolved in fixed F108 solution is presented in Tab. 2-7-2 and

Tab. 2-7-4.

Tab.2-7-2: Apolar oils and alcohols

Oils

Formula

Mw[g．mol-1]

Company

1-Hexanol

C6H14O

102.18

Merck

Toluene

C6H5CH3

92.14

Merck

Geraniol

C10H18O

154.25

ALDRICH

Ethanol

C2H5OH

46.07

Merck

1-Butanol

C4H9OH

74.12

Merck

1-Octanol

C8H17OH

130.23

Merck

2nd Part: Phospholipids DMPC and diesterquat CR3099

Part of DLS

Phospholids DMPC are reserved in the refrigerator under -30oC as white powder. When

DMPC is hydrated, there are large unilamellar vesicles at different sizes in the solution.

Forming the small unilamellar vesicles of DMPC is controlled by means of extrusion.

Diesterquat CR3099 appears as a yellow, viscose liquid and is reserved in a cool place

without sunlight and at room temperature. Pure CR3099 dissolves in water and appears

turbid and homogenous solutions. It forms large vesicles homogenously in the solution.

Forming the small unilamellar vesicles of CR3099 is controlled by means of extrusion.

Filters for 100 nm in diameter are chosen for the formation of the small vesicles. The

numbers of extrusion times are at least 5 times; the number of 10 times shows the best

efficency for keeping the long time of the stable small vesicles in the solution. For the case

of CR3099, the samples of CR3099 are extruded only five times. Additives are added into

the DMPC and CR3099 solutions respectively before extrusion.

Tab. 2-7-3: Phospholipids

Name

Structural formula

Mw[g．mol-1]

Company

1,2Dimyristoyl

sn-Glycero-3-

Phosphocholine

(DMPC)

OPO

N+

O-

677.94

Avati® polar

Lipids, Inc.

1,2Dihexanoyl-

sn-Glycero-3-

Phosphocholine

(DHPC)

OPON+

O-

453.51

Avati® polar

Lipids, Inc.

Tab. 2-7-4: Copolymers

Structural formula

Mw[g．mol-1]

Company

PPO

HO[CH3CHCH2O]H

1000.0

ALDRICH

Rewopal

6000

C17H35

O150

7160

Evonik

Kollicoat® IR

(Polyvinyl

alcohol-

polyethylen

e glycol)

OOOOOO

470.60

BASF

Kollicoat®

MAE 30 DP

*H2

COOH

COOC2H5

n m

250000

BASF

Part of Stopped Flow

The DMPC solution, which has already been extruded, is prepared with ions. There are

FeCl3 at 2 mM, NH4SCN at 6 mM and NaNO3 at 200 mM in the DMPC solution. Making

the sonication for one hour, it lets the small vesicles and ions homogenous completely in

solution. The presence of 200 mM NaNO3 is because of 200 mM NaF solution in order to

prevent the osmotic effect, when they are mixed.

3rd Part: Gel solution of TDMAO, TTABr and 1-Hexanol

The zwitterionic surfactant TDMAO was a noble and worthy gift as a liquid phase from the

company of STEPAN. The TDMAO was processed before use with the following process:

First, the liquid TDMAO was frozen in the round flask by liquid nitrogen. After that, it was

put in the lyophilisation instrument for one week. As a result, it turned into powder. The

final solution was prepared by proceeded TDMAO together with TTABr and 1-Hexanol,

which were used as received. They are soluble together in water as the gel phases. In this

experiment, three parent solutions were prepared at different ratios of TDMAO, TTABr and

1-Hexanol. The presence of an additive is dissolved directly in the parent solution.

Tab. 2-7-5: Surfactants

Name

Structural formula

Mw[g．mol-1]

Company

Tetradecyldimethylami

neoxide (TDMAO)

N+

O-

246.75

Stepan

Tetradecyltrimethylam

monium bromide

(TTABr)

N+

Br-

336.41

ALDRICH

Di-Oleic Acidyl

Isopropylester

Dimethylammonium

Methosulfate

(Diesterquat_CR3099)

N+

662

Evonik

3. Solubilization of oils of different polarity in PEO-PPO-PEO

copolymers – Effects on the aggregation behaviour

Investigating the thermal characteristics of Pluronic triblock copolymers has been

proceeding for over twenty years. The chemical structure is of the type EOn-POm-EOn or

POm-EOn-POm in general; it is one of the most useful amphiphilic surfactants in a variety of

applications, such as stabilizers, gene therapy, drug delivery, vesicles, gel materials [58-

61], etc. The temperature sensitivity is mainly because of the PPO blocks. The PPO

blocks are soluble in water at low temperatures and start to dehydrate if the temperature

is reached over the deciding point, which named as the critical micelles temperature (cmt).

They are dependent on the concentration as well, and at a constant temperature they will

turn hydrophobic once the critical micelles concentration (cmc) is reached. At low

temperatures, the blocks of PPO are more hydrophilic than the blocks of PEO. They exist

as individual unimers and if the temperature increases, the PPO blocks become more

hydrophobic and the hydrophobic PO prefers to aggregate. With the hydrophilic blocks of

PEO surrounding the aggregated PPO blocks, they form micelles in the solution, provided

the solution is already over cmt and cmc. The micellar phases in water are homogeneous

and transparent. There is no macroscopic difference between the unimer and the micelle

phases.

There are lots of methods to determine the values of cmc and cmt such as NMR

spectroscopy, fluorescence spectroscopy, surface tension meter and calorimeter methods,

like isothermal titration calorimetry (ITC) and Differential scattering calorimeters (DSC),

which have been published [62-67]. In this work, DSC is used to determine cmt values of

fixed pluronic solutions in the presence of polar oils and other kinds of copolymers,

respectively, and to characterize the aggregtion process correspondingly. The pluronic

F108 was selected as a rather hydrophilic copolymer surfanctant and mainly

concentrations of 3.6 mm and 7.0 mm were employed. The polar oils of 1-Hexanol,

Toluene, and geraniol were selected as representative solubilizates of different polarities.

In this system, cmt values were previously determined by means of fluorescence

spectroscopy (diploma thesis and these values are given in the appendix). In this work the

calorimetric aspects of such solubilization are studied and compared to structural

investigation by means light scattering and neutron scattering.

1-Hexanol can be solubilized at the highest amounts of all the apolar oils. Its solubility

capacity has been tested to be homogenous, at least 150 mm in 3.6 mm F108 solution; by

the way, the 200 mm 1-Hexanol appears turbid. For a comparison other primary alcohols

were also studied, such as ethanol, 1-Butanol and 1-Octanol. For F108 solutions of 7.0

mm, correspondingly higher solubilization capacities are expected. In addition to the

oils/alcohols, the pure homopolymer PPO at ca. 1000 g‧mol-1 was selected to analyse its

effect on phase behaviour and thermal properties at first, thereby comparing to a

polymeric oil.

Let us know think back to the topic of my diploma dissertation, which focused on the

solubilisation of polar oils in fixed solutions of the triblock copolymer F108. It tried to

determine the solubility capacity of each selecting apolar oils in the F108 solution

respectively by the macroscopic and microscopic methods. Analysing the modification of

fluorescence absorbance is measured dependent on temperature in order to determine

the cmt values. The force between the F108 solution and each of the oils was also

discussed in the dissertation and they were analysed from 15oC to 40oC by means of

interfacial force of spinning drop. Continuing this work, my doctoral dissertation

investigates the thermal characteristics of triblock copolymers. Selecting the same triblock

copolymer F108 solubilized with the reduplicate oils, like 1-Hexanol, Toluene, geraniol and

homo copolymer PPO. The polymer Kollicoat MAE 30 DP, which has been used in

pharmaceutical applications, is selected as an additive in the F108 solution; it is more

hydrophilic in comparison to other additives. There are other additives in the group of

primary alcohol, such as Ethanol, 1-Butanol and 1-Octanol, which is used for investigating

thermal properties of F108. The analysis methods are differential scattering calorimeters

(DSC), dynamic light scattering (DLS), small angle neutrons scattering (SANS) and

viscosity. All the samples are measured by the DSC method and the cmt values and

enthalpy of △H(PO) are determined for each of samples. In the presence of oils, normally

the cmt decreases, this has been proved in my master’s dissertation by the method of

fluorescence spectroscopy. However, some additives, like PPO and Kollicoat MAE 30 DP,

result in another appearance. The size of micelle phases was analysed by DLS. They

were measured dependent on temperature in order to observe the dehydration process of

the hydrophobic blocks. The hydrodynamic radius Rh is determined by the ALV 7004

Correlator software with methods of Simple Fit and Regularized Fit. The results of SANS

give us additional information to reconfirm the existence of 1-Hexanol most in F108 not in

D2O solutions. The intensity I (q) is increased markedly in the presence of 1-Hexanol at a

fixed q position.

3-1 F108 solution

As the PPO blocks of F108 are sensitive to temperature, the unimer F108 phases can turn

to micelle phases in the aqueous solution with increasing temperature. While the

macroscopic appearance of the F108 solution is little affected by this transition (unimer

and micelle phases are both homogeneous and transparent), it can be detected by the

DSC method.

010 20 30 40 50 60

-1000

-800

-600

-400

-200

200 010 20 30 40 50 60

-200

200

400

600

800

1000

T/ oC

uJ/ s

F108 /mm

3.6 mm

7.0 mm

10 mm

15 mm

F108 solution at 0.5 oC/min.

Fig. 3-1-1a and 1b : Thermal peaks of 3.6 mm, 7.0 mm, 10 mm and 15 mm F108 solution in

heating (1a) and cooling (1b) processes as function of temperature.

The concentration of F108 solution is increased from 3.6 mm to 15 mm and signals

appear in the heating and cooling process by means of the DSC instrument. The signals

are an endothermic and an exothermic peak for both processes, respectively. With

increasing temperature, the PPO blocks become dehydrated and more hydrophobic. The

dehydration of PPO blocks is an endothermic reaction. In other words, if the temperature

decreases, the PPO blocks start to be hydrated and release the energy again. With higher

concentrations of F108, the endothermic and exothermic peaks are shifted to higher

temperatures.

Tab.3-1-1: Tonset and Tpeak of F108 in thermal process

The endothermic and exothermic peaks of increasing concentrations of F108 from 3.6 mm

to 15 mm as a function of temperature are presented in Fig.3-1-1 and 3-1-2. Two positions

of temperature are taken into consideration. They are calleded Tonset and Tpaek. Tonset is at

the point at which thermal reaction begins [68] and Tpeak at the highest point of the thermal

peaks. Both temperatures are used commonly as a cmt point to determine the micelle

phases in the solution [11, 69-71]. There is another method for cmt determination, which is

called the inflection point temperature (Tinf) by Hecht and Hoffmann [72]. The temperature

Tinf is not discussed in this dissertation. With increasing amounts of F108, lower values of

Tonset and Tpeak are observed.

Tab.3-1-2: Intergration Q and ΔH(PO) of F108 solution in thermal process

Integration Q and ΔH(PO) of variable F108 solution / mm at 0.5 oC/ min

Integration Q/mJ

ΔH(PO)/ kJmol-1

F108/ mm

Heating

Cooling

Heating

Cooling

3.6 mm

194.2

189.1

3.79

3.70

7.0 mm

386.3

372.1

4.10

3.95

10 mm

510.2

498.6

3.96

3.87

15 mm

735.7

711.8

4.08

3.95

Tab. 3-1-2 summarizes the integration area and the enthalpy of each PO unit for F108

solutions with the concentration from 3.6 mm to 15 mm. The integration area is

proportional to the amounts of F108 copolymer. The 15 mm F108 solution results the

highest endothermic and exothermic peak and the maximal values of the integration. After

calculation, the enthalpy of each PO unit is on average around 4.0 and 3.9 kJmol-1.

Another publication results enthalpy ΔH (PO)50 of F108 copolymer 220 kJmol-1 equally when

the concentration is from 2% to 10%. The enthalpy is influenced by the measuring

scanning rate. The scanning rate of 0.5oC/min. results in an enthalpy higher than

0.2oC/min. The enthalpy of dehydration from this experiment and publication shows the

same results that the values become constant when the concentration of F108 is

increasing [10].

F108 solution at scan rate of 0.5 oC/min

Heating process

Cooling process

F108/ mm

T onset

T peak

T onset

T peak

3.6

26.6

31.1

39.1

29.6

7.0

23.6

27.1

37.5

25.6

21.4

25.1

34.3

23.5

17.3

21.2

29.2

19.5

3-2 Mixtures of apolar oil and F108 solution

The polar oils, like 1-Hexanol, geraniol and Toluene, were studied in mixtures with

different concentrations of F108 solutions. The high amounts of F108 could be hard

dissolve in water at room temperature. The phase behaviour of F108 solution at high

concentrations, like 10 mm and 15 mm, is still transparent and homogenous, but it turns

into a gel and becomes more viscous upon adding the solubilisate. The phase behaviour

of F108 copolymers form unimer phases, micelle phases and lamellar phases in aqueous

solutions dependent on concentration. However, they are all transparent and

homogeneous under macroscopic observation. The admixture of 1-Hexanol, geraniol has

been shown before by fluorescence spectroscopy to lower the critical micelle temperature,

by analysing the ratio of I1 and I3 with Pyren in solution [73]. More comprehensive

information was obtained here by the DSC method. The appearance of thermal peak

position at given temperature allows to deduce precisely the cmt values and its integration

gives the dehydration enthalpy of PO.

Phase Behaviour

Polar oils, PPO and 3.6 mm F108 solution

Fig. 3-2-1: Photo of samples containing various polar oils and PPO in a 3.6 mm F108

solution

The copolymer F108 was dissolved in water directly without any purification. They are

used for parent solutions at the concentration of 3.6 mm and 7.0 mm. The selecting oils 1-

Hexanol, geraniol, PPO, etc., were dissolved directly in the parent solution, respectively.

Depending on their solubility, the highest amounts of them prepared are not the same. Fig.

3-2-1 shows the homogeneity and transparency of the samples.

3-2-1 1-Hexanol and F108 solution

This part presents the nano DSC measurements of 1-Hexanol, which is mixed with two

different fixed parent solutions of 3.6 mm and 7.0 mm F108. The chemical structure of 1-

Hexanol is similar to that of surfactants, with a hydrophobic and a hydrophilic part, but it

can not form micelles itself. Such molecules can be classified as cosurfactant. 1-Hexanol

0, 10, 20, 80 mm Hexanol

2, 5, 10 mm Geraniol

5, 10 mm Toluene

3, 10 mm PPO

dissolves somewhat in aqueous solutions (5.9 g/L or 57 mm at 20 oC), but the F108

solution can dissolve much more 1-Hexanol than pure water. The reason can be due to it

containing the hydrophobic and hydrophilic character of PEO-PPO-PEO blocks in the

solution. The values of Hildebrandt parameters between 1-Hexanol and F108 are close

each other, and relatively far from water. The F108 forms the extra hydrophilic and

hydrophobic area in water that provides another environment for 1-Hexanol to coexist.

1-Hexanol and 3.6 mm F108

For the case of 3.6 mm F108, we studied 1-Hexanol concentrations of 0-100 m in the

temperature range of -10 to 60oC by DSC heating and cooling cycles.

-20 -10 0 10 20 30 40 50 60

-200

-150

-100

-50

100 010 20 30 40 50 60

-100

-50

100

150

200

T/ oC

J/s

1-Hexanol in 3.6 mm F108 at 0.5 oC/min

1-Hexanol

0 mm

10 mm

20 mm

30 mm

60 mm

80 mm

100 mm

Fig. 3-2-1-1a and 1b: 1-Hexanol in 3.6 mm F108 as a function of temperature in heating(1a)

and cooling(1b) processes.

In the heating and cooling process of 1-Hexanol and 3.6 mm F108 solution, the

endothermic and exothermic peak appear in the range from 0oC to 60oC. The samples of

80 mm and 100 mm were measured in the heating process from 0oC to 60oC and cooling

down from 60oC to -10oC (see Fig. 3-2-1-1a and 1b). The transformation of 1-Hexanol

containing the 3.6 mm F108 aqueous solution is a fully reversible process. The

endothermic and exothermic peaks of 3.6 mm F108 shift to lower temperatures with

increasing concentrations of 1-Hexanol. At low concentrations of 1-Hexanol, only the

position of peaks is affected but not the shape. If the concentration of 1-Hexanol is

increased above 60 mm, the peak shape becomes deformed. It could be the solubility of

1-Hexanol due to the low temperature decreasing. Limiting the set up of this instrument

does not let the process start at subzero temperatures in the heating process, but in the

cooling process can continue the measurements under 0 to -10oC. The samples of 80 mm

and 100 mm begin to form micelle phases at a similar position of Tonset in the heating

process and 100 mm results higher intensity than 80 mm 1-Hexanol.

Tab. 3-2-1-1: Tonset and Tpeak of 1-Hexanol and 3.6 mmF108 in thermal process

Tab. 3-2-1-1 summarizes the temperatures of oneset and peak with variable concentration

of 1-Hexanol in 3.6 mm F108 solution. T onset und T peak values are both used to discuss the

formation of micelle phases, i.e., by the critical micelle temperature. Both, T onset and T peak

of 3.6 mm F108 solution decrease proportionally to the concentration of 1-Hexanol.

Tab.3-2-1-2: Integration Q and ΔH(PO) of 1-Hexanol and 3.6 mm F108 solution in thermal

process

Integration Q and ΔH(PO) of 3.6 mm F108 with the variation of 1-Hexanol/ mm at 0.5 oC/ min

Integration Q/mJ

ΔH(PO)/ kJmol-1

1-Hexanol

Heating

Cooling

Heating

Cooling

0 mm

194.2

189.1

3.79

3.70

10 mm

204.2

199.8

4.00

3.90

20 mm

215.2

206.9

4.21

4.04

30 mm

237.9

226.1

4.65

4.42

60 mm

284.1

278.0

5.55

5.43

80 mm

305.3

5.97

100 mm

333.4

6.51

Tab. 3-2-1-2 summarizes the integration area and enthalpy of PO pro unit of the 3.6 mm

F108 with the mixture of 1-Hexanol. The integrated heat Q increases with the addition of

1-Hexanol and is proportional to the 1-Hexanol concentration at the fixed F108 solution.

The enthalpy of ΔH (PO) also increases in the presence of 1-Hexanol and indirectly proves

that the PO blocks interact with the 1-Hexanol. In other words, 1-Hexanol as a

cosurfactant enhances the efficiency of the dehydration of each PO block. Indirectly it is

1-Hexanol in 3.6 mm F108 solution at scan rate of 0.5 oC/min

Heating process

Cooling process

1-Hexanol/ mm

T onset

T peak

T onset

T peak

26.6

31.1

39.1

29.6

24.2

29.0

38.3

27.4

22.8

27.9

36.2

26.4

18.3

24.6

33.7

23.1

12.5

19.5

30.4

17.9

4.20

13.8

26.8

12.5

100

4.50

12.3

24.5

4.70

proved that certain amounts of 1-Hexanol are dissolved in hydrophobic parts of PPO. The

solubility of 1-Hexanol in water is low but is enhanced in the presence of F108. The

thermal peaks for the sample of 80 and 100 mm are not complete in the heating process,

so only the results are presented for the cooling process in the table.

020 40 60 80 100

3,5

4,0

4,5

5,0

5,5

6,0

6,5

H(PO)/ KJmol-1

The polar oil in 3.6 mm F108 in cooling process

dHPO/dc1-Hexanol

=0.029 KJmol-1mm-1

1-Hexanol/ mmol

R=0,997

Fig. 3-2-1-2: Enthalpy ΔH(PO) of 1-Hexanol in 3.6 mm F108 as function of concentration

Fig. 3-2-1-2 shows the enthalpy △H(PO) of fixed 3.6 mm F108 in the presence of 1-

Hexanol as a function of concentration. After linear fit calculation, the value R is 0.997.

The result shows the optimal linear function. In the 3.6 mm F108, the solubility capacity of

1-Hexanol is not reached. The maximal of 1-Hexanol can be increased to 150 mm

homogeneously in the F108 solution. In the presence of 1-Hexanol it is useful for the F108

solution to increase the energy of the dehydration and hydration processes.

1-Hexanol and 7.0 mm F108

010 20 30 40 50 60

-400

-300

-200

-100

100

200 010 20 30 40 50 60

-200

-100

100

200

300

400

T/ oC

1-Hexanol and 7,0 mm F108 solution at 0,5 oC/ min.

1-Hexanol/ mm

0 mm

15 mm

30 mm

60 mm

80 mm

100 mm

uJ/s

Fig. 3-2-1-3a and 3b: 1-Hexanol in 7.0 mm F108 as a function of temperature in heating (3a)

and cooling(3b) processes

Also for admixtures of 1-Hexanol to 7.0 mm F108 solutions, the endothermic and

exothermic peaks appear in the range from 0 to 60oC in the heating and cooling

processes. Figures 3-2-1-3a and 3b indicate that the 7.0 mm F108 solution, which is

mixed with 1-Hexanol, forms the micelle phases. The process of dehydration is reversible.

Interestingly, the sample containing no 1-Hexanol shows the sharpest endothermic and

exothermic peaks. Addition of the 1-Hexanol lowers the height of endothermic and

exothermic peaks and the peaks shift to lower temperatures. The shapes of peaks

become deformed if the concentration of 1-Hexanol is over 60 mm. It could be the low

solubility of 1-Hexanol at low temperatures in the F108 solution. The result is similar to the

3.6 mm solution. The sample for 100, 80 mm could form complete endothermic and

exothermic peaks under the experimental conditions of the Nano DSC measurements.

Tab.3-2-1-3: Tonset and Tpeak of 1-Hexanol and 7.0 mmF108 in thermal process

1-Hexanol in 7.0 mm F108 solution at scan rate of 0.5 oC/min

Heating process

Cooling process

1-Hexanol/ mm

T onset

T peak

T onset

T peak

23.6

27.1

37.5

25.6

19.4

24.5

32.4

23.0

15.7

21.4

30.5

19.9

9.1

17.6

28.2

16.2

4.8

14.6

25.0

12.3

100

3.0

6.4

23.5

9.9

Tab. 3-2-1-3 shows the reduction T onset and T peak in heating and cooling process for 7.0

mm F108 solution that is proportional to the amount of 1-Hexanol contained. In the

presence of 1-Hexanol it is useful for 7.mm F108 solution to be successionally decreased.

Tab.3-2-1-4: Intergration Q and ΔH(PO) of 1-Hexanol and 7.0 mm F108 solution in thermal

process

Integration Q and ΔH(PO) of 7.0 mm F108 with the variation of 1-Hexanol/ mm at 0.5 oC/ min

Integration Q/mJ

ΔH(PO)/ kJmol-1

1-Hexanol

Heating

Cooling

Heating

Cooling

0 mm

386.3

372.1

4.10

3.95

15 mm

391.2

382.8

4.16

4.07

30 mm

419.3

391.3

4.45

4.16

60 mm

452.5

397.8

4.81

4.23

The results of integration and enthalpy of ΔH(PO) from the endothermic and exothermic

peaks of the 7.0 mm F108 solution, composed of 1-Hexanol, are given in Tab. 3-2-1-4.

The 7.0 mm F108 solution shows higher values of integration than 3.6 mm F108, because

7.0 mm F108 contains more hydrophobic blocks of PPO than 3.6 mm F108. However, the

ΔH(PO) results are almost the same, which demonstrates that this enthalpic process has to

be asociated with the PO. The presence of 1-Hexanol increases the enthalpy of PO

dehydration appreciably and ΔH(PO) is proportional to the concentration. The 7.0 mm F108

solution is more soluble with more than 100 mm 1-Hexanol. The amount of 1-Hexanol has

been increased to 300 mm in 7.0 mm F108 homogenously and was analysed by

fluorescence spectroscopy (see appendix). The values of Tonset and Tpeak will decrease

close to 0oC. Tab. 3-2-1-4 summarized the results from 0 to 60 mm, because the thermal

peaks for the samples of 80 and 1 00 mm are not complete in either process. After

calculation both are not accurate in reality.

Results of SANS measurements

The 3.6 mm F108 is analysed intensively by means of the neutron scattering method. The

SANS data provides us the details that the behaviour of 3.6 mm F108 induces in the

presence of increased 1-Hexanol at a constant temperature. The data can be analysed by

the program of SASfit [45]. The samples were prepared ready in Stranski-Laboratorium

and measured at HzB by Dr. Sylvain Prévost.

1-Hexanol in the 3.6 mm F108 D2O solution

0,1 1

0,1

I(q)/cm-1

q/nm-1

1-Hexanol/ mm

0 mm

6 mm

12 mm

20 mm

30 mm

50 mm

1-Hexanol and 3.6 mm F108 in D2O at 25C

Fig. 3-2-1-4: SANS data of 1-Hexanol in the 3.6 mm F108 D2O solution at 25°C (with fit data)

The models of background, Gauss and core shell i with hard sphere have been selected

to fit the F108 SANS measurements in the presence of 1-Hexanol. The fitting equations

are selected von the Gauss model with eq. 2-3-17 and Spherical shell i model with the

structure factor Hard Sphere. The form factor von Spherical shell i model is the eq. 2-3-21

and the structure factor of Hard Sphere is followed by eq. 2-3-24.

Fig. 3-2-1-4 shows results of SANS for samples with 1-Hexanol from 0 to 50 mm in 3.6

mm F108 in D2O, respectively. The presence of 1-Hexanol increases the intensity at low q

and middle q position. The D2O samples were all measured at room temperature around

25oC and are under of cmt of the pure 3.6 mm F108 solution. The presence of the 1-

Hexanol leads to an increase of scattering intensity, where this increase is particularly

pronounced in the range of 15-20 mm. Apparently for lower 1-Hexanol content, one has

unimers present, which then become transformed to micelles for higher 1-Hexanol content.

For the unimer solutions of F108, the radius of gyration Rg, which means the size of the

individual F108 copolymers, was determined by a coil model with the Debye equation [54,

74]. Small amounts of 1-Hexanol can be dissolved in the unimer phase of F108 and D2O

without altering the structure much. When 1-Hexanol increases to 50 mm, the intensity of

I(q) remains equal to the 30 mm 1-Hexanol at low q but a correlation peak is developing.

The solubility capacity of unimer and D2O is saturated and the extra 1-Hexanol still can be

dissolved in the aggregates of F108. A Spherical shell i model (Fig. 2-3-3) was employed

in the analysis of the SANS data and was fitted to the data using the software program

SASfit. The best fit results are presented with the SANS data in Fig 3-2-1-4. Three models

have been selected, which is background, Gauss and spherical shell i including of hard

sphere, in order to do calculations of the SANS measurements by the SASfit software.

Tab. 3-2-1-5: Input paramenters of form factors and the structure factor for the 3.6 mm F108

in the presence of 1-Hexanol

3.6mm F108

Background

Gauss

Spherical Shell i

Hard sphere

1-Hexanol

[mm]

Iinc

[cm-1]

[nm]

Nagg

[nm]

[nm-2]

eta

[nm-2]

RHS

[nm]

0.055

0.51

2.31

0.059

0.51

2.31

0.36

9.6

3.9

15.18

8.7E-5

11.36

0.021

0.061

0.52

2.31

1.58

9.6

3.9

15.18

8.7E-5

11.36

0.047

0.060

0.51

2.31

10.62

9.6

3.9

15.18

8.7E-5

11.36

0.075

0.063

0.48

2.31

21.63

9.6

3.9

15.18

8.7E-5

11.36

0.113

0.061

0.36

2.31

42.27

9.6

3.9

15.18

8.7E-5

11.36

0.188

The results of the parameters are summarized in Tab. 3-2-1-5. The background Iinc is one

of the parameters from the Porod approximation at the beginning of an integral structure.

It is like the noise correction of scattering. The Gauss model describes the random walk

for a polymer chain in a solution. The parameters of the Gauss model are I0 and Rg. Rg is

the gyration radius and I0 is forward scattering at q=0. The form factor of Spherical shell i

is parameterized with an inner radius R2 and outer radius R1. The parameter of △η is the

scattering length density difference between shell and solvent. mu is the scattering length

density difference between the core and solvent, relative to the shell contrast (see. Fig. 2-

3-3). RHS is a hard sphere radius. The six samples in the presence of increasing 1-

Hexanol respectively make a multiple fit calculation and the results are summarized in Tab.

3-2-1-5. In Fig. 3-2-1-4, the each of the fit dates corresponds to their measurements.

Some parameters are in question, like the parameter I0 from Gauss model. It leads to a

decreasing value when the 1-Hexanol is increasing, but the curve presents the contrary.

The gyration radius Rg has the same result at a radius of 2.31 nm with increasing amounts

of 1-Hexanol because the unimer phases are only from F108 and at the fixed solution of

3.6 mm. Other radius parameters, like R2, R1 and RHS, remain constant result in the

presence of 1-Hexanol. Those radiuses indicate indirectly the size of the triblock

copolymer F108 after dehydration effects, in other words, the size of micelle phases. They

indicate the size and distance of each micelle when the copolymers of F108 have been

aggregated. The presence of 1-Hexanol does not influence the size of particles; however,

the parameter N is improved. Nagg are the numbers of aggregation and can be calculated

by the characteristics of the components (molecular, volumenn and SLDs) and the total

volume fraction of additives [75].

Normally the micelles are expected to have a high-density compact core, which is a

hydrophobic part of PO blocks and a low-density compact corona, which is the hydrophilic

part of EO blocks. These parameters are presented as a scheme in Fig. 3-2-1-4. In the

absent of 1-Hexanol the 3.6 mm F108 is measured under critical micelle temperatures. In

the presence of 1-Hexanol it leads the critical micelle temperature of 3.6 mm F108 to go

down. At a constant temperature like 25oC the aggregation numbers of F108 copolymers

grow with increasing amounts of 1-Hexanol. The model of Spherical shell i is concerned

about Hard sphere, which contains two parameters RHS and fp. RHS is called the hard

sphere radius, which is the distance between two particles, and fp is the volume fraction.

010 20 30 40 50

0,00

0,04

0,08

0,12

0,16

0,20

RD2O/ nm

1-Hexanol/ mmolkg-1

RHS

1-Hexanol and 3,6 mm F108 in D2O at 25 oC

Fig.3-2-1-6: Results of R1, R2, RHS and fp as a function of 1-Hexanol in mm

Fig. 3-2-1-6 summarizes the results of inner and outer radiuses R2 and R1, Hard sphere

radius RHS and volume fraction fp as function of 1-Hexanol in mm. The outer R1 and inner

R2 radius result in no changes with increasing amounts of 1-Hexanol. The radius R1 can

look on as the size of F108 after aggregation and R2 is the hydrophobic part of PPO

blocks from F108. Comparing with the DLS measurements the SANS present a similar

size in the aggregation process. The presence of 1-Hexanol leads to no influences that

modify the radius of F108 copolymer. The Hard sphere radius keeps constant with

increasing amounts of 1-Hexanol. The aggregation of F108 distributes homogenously in

the solution. There are no attractive effects for 1-Hexanol as a bridge that packed each

micelle or aggregation densely. However, the increasing of volume fraction fp indicates the

existence of 1-Hexanol in the solution. The high scattering intensity I(q) grows at the same

q position in the middle, indicating that 1-Hexnaol dissolved in the parts of F108

copolymers after aggregations have been already formed. The low q position appears with

high intensity in the presence of 1-Hexanol. The fixed solution of 3.6 mm F108 at 25oC is

under the cmt, which is determined by the DSC method. Some amounts of 1-Hexanol

could be soluble the unimer phases of F108. There are some parameters, like mu eta and

Rg that are not presented in Fig. 3-2-1-7. The gyration radius of Rg results in a constant

radius after SASfit calculations with increasing amounts of 1-Hexanol. It appears to have

no influence on modifying the unimer radius in the presence of 1-Hexanol.

0,1 1

0,1

I(q)/ cm-1

q/ nm-1

1-Hexanol/ mm

0 mm

6 mm

12 mm

20 mm

30 mm

50 mm

80 mm

100 mm

1-Hexanol in 3.6 mm F108 in D

2O at 25 oC

Fig.3-2-1-7: SANS data of the 1-Hexanol in 3.6 mm F108 D2O solution (without fit data)

The samples of 80 and 100 mm 1-Hexanol in 3.6 mm F108 were measured recently by Mr.

Raphael Michel at ILL in Grenoble after the samples from 0 to 50 mm. Compared with the

old dates, the scattering intensity continues to increase at the middle q position when the

concentration of 1-Hexanol increases to 100 mm. The phase behaviour of SANS samples

for 80 mm and 100 mm is transparent and homogenous. They are dissolved mostly in the

core – shell of F108 aggregations. The scattering intensity of 80 mm and 100 mm 1-

Hexanol is not measured at the low q position, so it is hard to investigate the influence

with the old data. SANS data of Fig. 3-2-1-7 have been fitted by Dr. Sylvain Prévost and

published [76].

0,1 1

0,1

1-Hexanol in 7.0 mm F108 in D2O at 25 oC

I(q)/cm-1

q/nm-1

1-Hexanol/ mm

0 mm

20 mm

40 mm

60 mm

Fig.3-2-1-8: SANS data of the 1-Hexanol in 7.0 mm F108 D2O solution (with fit data)

At a fixed concentration of 7.0 mm F108 in D2O is measured by the SANS method in the

presence of 1-Hexanol from 0 to 60 mm. The samples contain similar amounts of 1-

Hexanol (see Fig. 3-2-1-4) and the F108 solution is increased to 7.0 mm. From the results

of Nano DSC the 7.0 mm F108 has been already aggregated at 25oC. At the low q

position there appears to be no increasing scattering intensity in the presence of 1-

Hexanol. However, I(q) increases at the middle q position with increasing amounts of 1-

Hexanol. Most of the triblock copolymers have been dehydrated at 25oC at a

concentration of 7.0 mm in the solution. 1-Hexanol prefers to stay in the aggregation of

F108 than the aqueous solution, when micellization conditions of the F108 solution is

comformed even if it can be soluble in at least 40 mm in water. Fig. 3-2-1-8 presents the

best fit curve for each of the samples, which are analyzed by SASfit. The models of

Background, Gauss and Spherical Shell i models including Hard sphere are selected. The

results of fit parameters existed questionably, like 3.6 mm F108 in D2O, so they will not be

summarized in this dissertation.

3-2-2 Geraniol and F108 solution

The polar oil geraniol appears clear and the solublity in water is 686 mg/L, which is equal

to 4.45 mm at 20oC [77]. The organic compounds of Geranial – an allyl alcohol with an

acyclic monoterpene chain length, which is one kind of flavour chemical –, can be

synthesized and extracted from plants, such as lavender, geranium, roses, orange leaves

and lemon peels. Although geraniol is dissolved in water very low, the solubility is

increased in the presence of F108. The solubility parameters of F108 and geraniol are

similar. It can be predicted that they can be soluble to each other in aqueous solutions.

Geraniol and 3.6 mm F108

For the case of 3.6 mm F108, we studied geraniol concentrations of 0 to 13 m in the

temperature range of 0 to 60 oC by DSC heating and cooling cycles.

010 20 30 40 50 60

-200

-150

-100

-50

100 010 20 30 40 50 60

-100

-50

100

150

200

uJ/s

T/ oC

Geraniol and 3.6 mm F108 solution at 0.5 oC/min.

Geraniol

0 mm

2.5 mm

5 mm

10 mm

13 mm

Fig. 3-2-2-1a and 1b: Geraniol in 3.6 mm F108 as a function of temperature in heating (1a)

and cooling (1b) processes

3.6 mm F108 solutions in the presence of geraniol from 0 to 13 mm have shown, in Fig. 3-

2-2-1a and 1b, the thermal peaks via the DSC measurements in the heating and cooling

processes. The highest peak intensity is reduced in the presence of geraniol and the peak

width gets broader. The peak position shifts to the lower temperature when the

concentration of geraniol is increased in the 3.6 mm F108 solution. At high concentrations

of Geranial, like 5 mm, a slightly deformed endothermic peak appears, although in the

cooling process a broadening exothermic peak appears. If geraniol continues to increase

to 10 and 13 mm in 3.6 F108 solutions, strongly deformed thermal peaks in both

processes are present. When the amounts of Geranilo are increased, the scanning curves

show unstable signals around the baseline especially at low temperature.

Tab. 3-2-2-1: Tonset and Tpeak of Geraniol and 3.6 mmF108 in thermal process

Geraniol in 3.6 mm F108 solution at scan rate of 0.5 oC/min

Heating process

Cooling process

Geraniol/ mm

T onset

T peak

T onset

T peak

26.6

31.1

39.1

29.6

2.5

20.4

29.3

38.5

27.5

5.0

16.2

27.8

37.4

25.9

14.4

25.0

36.5

23.2

11.6

22.8/19.5

35.2

21.4

Tab. 3-2-2-1 summarized the values of Tonset and T peak for the samples of geraniol from 0

to 13 mm in the 3.6 mm F108 solution, respectively, in both thermal processes. In the

presence of geraniol reduces 3.6 mm F108 solution the values of T onset and Tpeak. The

decreasing temperature is proportional to the amounts of geraniol. The solubility capacity

of geraniol in 3.6 mm F108 solution is lower than 1-Hexanol, so in this experiment the

geraniol is prepared till 13 mm. The deformed peak appears at two high points for the 13

mm sample in the heating process. Therefore, there are two peak temperature values for

the 13 mm sample geraniol.

Tab.3-2-2-2: Integration Q and ΔH(PO) of Geraniol and 3.6 mm F108 solution in thermal

process

Integration Q and ΔH(PO) of 3.6 mm F108 with the variation of Geraniol/ mm at 0.5 oC/ min

Integration Q/mJ

ΔH(PO)/ kJmol-1

Heating

Cooling

Heating

Cooling

0 mm

194.2

189.1

3.79

3.70

2.5 mm

206.1

195.0

4.03

3.81

5.0 mm

223.7

206.5

4.37

4.04

10 mm

253.2

222.2

4.95

4.34

13 mm

261.0

238.3

5.10

4.66

The results of integration Q and ΔH (PO) enthalpy for the samples of geraniol in the 3.6 mm

F108 solution is presented in Tab. 3-2-2-2. The integration of the thermal peak is

increasing with the addition of geraniol and is dependent on the concentration. High

amounts of geraniol lead to the area of both thermal peaks being improved. The enthalpy

of ΔH (PO) also increases in the presence of geraniol, which means directly that it is

effective to improve the dehydration process of PO blocks.

Geraniol and 7.0 mm F108

For this case of 3.6 mm, F108 is increased to 7.0 mm and we studied geraniol

concentrations of 0 to 10 m in the temperature range of 0 to 60oC at scanning rate of

0.5oC/min. by DSC heating and cooling cycles.

010 20 30 40 50 60

-400

-300

-200

-100

100

200 010 20 30 40 50 60

-200

-100

100

200

300

400

T/ oC

uJ/s

Geraniol and 7.0 mm F108 solution at 0.5 oC/min.

Geraniol

0 mm

2.5 mm

5 mm

10 mm

Fig. 3-2-2-2a and 2b: Geraniol in 7.0 mm F108 as a function of temperature in heating (2a)

and cooling (2b) processes

As the diagrams 3-2-2-2a and 2b have shown, 7.0 mm F108 solutions in the presence of

geraniol from 0 to 10 mm the endothermic and exothermic reaction appear by the method

of the DSC in thermal cycles. The pure 7.0 mm F108 solution results in the intensity and

width of thermal peaks being stronger and narrower than in the pure 3.6 mm F108

solution. In the presence of geraniol the thermal peaks of 7.0 mm F108 shifts to the low

temperature and the intensity of peaks decreases, with the width of peaks broadening in

both scanning processes. The appearance of deformed peaks exists for the increased

concentration of 7.0 mm F108 in the presence of geraniol at low temperatures.

Tab. 3-2-2-3: Tonset and Tpeak of Geraniol and 7.0 mmF108 in thermal process

Geraniol in 7.0 mm F108 solution at scan rate of 0.5 oC/min

Heating process

Cooling process

Geraniol/ mm

T onset

T peak

T onset

T peak

23.6

27.1

37.5

25.6

2.5

18.2

26.4

34.8

24.8

5.0

15.1

25.8

34.1

24.1

10.0

11.2

23.6

32.5

21.9

Tab. 3-2-2-3 summarizes the values of T onset and T peak of the 7.0 mm F108 solution in the

presence of Geraniol from 0 to 10 mm respectively in both thermal processes. The pure 7

mm F108 solution results in a lower T onset and T peak than 3.6 mm F108 solution. The high

concentration of F108 leads to low temperatures of T onset and T peak. The presence of

geraniol is able to decrease temperature values of the 7.0 mm F108; the decreasing

temperatures of T onset and T peak are proportional to the quantity as well.

Tab.3-2-2-4: Integration Q and ΔH(PO) of Geraniol and 7.0 mm F108 solution in thermal

process

Integration Q and ΔH(PO) of 7.0 mm F108 with the variation of Geraniol/ mm at 0.5 oC/ min

Integration Q/mJ

ΔH(PO)/ kJmol-1

Geraniol

Heating

Cooling

Heating

Cooling

0 mm

386.3

372.1

4.10

3.95

2.5 mm

388.8

378.6

4.13

4.02

5.0 mm

425.0

393.3

4.51

4.18

10.0 mm

445.0

419.2

4.73

4.45

Table 3-2-2-4 summarizes the integration Q and enthalpy ΔH(PO) of Geraniol from 0 mm to

10 mm in 7.0 mm F108 solution. In the presence of Geraniol, the result is that the area of

thermal peaks increases and is dependent on the concentration. The enthalpy ΔH(PO) is

enhanced with increasing amounts of Geraniol in both thermal processes. Geraniol as a

co-surfactant is effective in the dehydration process of the 7.0 mm F108 solution.

3-2-3 Toluene and the F108 solution

Toluene is a clear and redolent solution, because it is an aromate derivative with a

benzene group. The solubility of toluene in aqueous solutions is 0.47g/L equal to 5.1 mm

and is enhanced in the presence of F108.

Toluene and the 3.6 mm F108 solution

In the case of 3.6 mm F108, we studied toluene concentrations of 0 to 20 mm in the

temperature range of 0 to 60oC at a scanning rate of 0.5oC/min. by DSC heating and

cooling cycles.

010 20 30 40 50 60

-200

-150

-100

-50

100 010 20 30 40 50 60

-100

-50

100

150

200

Toluene and 3.6 mm F108solution at 0.5 oC/min.

Toluene / mm

0 mm

5 mm

10 mm

20 mm

uJ/ s

T/ oC

Fig.3-2-3-1a and 1b: Toluene in 3.6 mm F108 as a function of temperature in heating (1a) and

cooling (1b) processes

The curves for toluene in 3.6 mm F108 solutions from 0 to 20 mm, respectively, are shown

in Fig. 3-2-3-1a and 1b. In the presence of toluene shifts the thermal peaks to low

temperatures in both processes. Besides, the heights of the thermal peaks tend to be

reduced, but the width of the peaks becomes broader depending on the concentration of

toluene. High amounts of toluene, like 20 mm, lead to the peaks being slightly deformed

and are observable in the heating process.

Tab.3-2-3-1: Tonset and Tpeak of Toluene and 3.6 mmF108 in thermal process

Toluene in 3.6 mm F108 solution at scan rate of 0.5 oC/min

Heating process

Cooling process

Toluene/ mm

T onset

T peak

T onset

T peak

26.6

31.1

39.1

29.6

5.0

26.5

30.7

38.9

29.1

24.2

30.0

37.9

28.3

18.2

27.9

37.7

25.8

Tab. 3-2-3-1 summarizes the values of Tonset and Tpeak in the presence of toluene from 0 to

20 mm in both processes. Both values result in a decrease with increasing amounts of

toluene. It indicates that toluene induces the temperature of dehydration of 3.6 mm F108

decreasingly. Toluene is effective in lowering the critical micellar temperature at the fixed

concentration of the F108 solution.

Tab.3-2-3-2: Integration Q and ΔH(PO) of Toluene and 3.6 mm F108 solution in thermal process

Integration Q and ΔH(PO) of 3.6 mm F108 with the variation of Toluene/ mm at 0.5 oC/ min

Integration Q/mJ

ΔH(PO)/ kJmol-1

Toluene/ mm

Heating

Cooling

Heating

Cooling

194.2

189.1

3.79

3.70

5.0

203.0

198.7

3.97

3.88

215.5

204.4

4.21

4.00

244.4

221.9

4.78

4.34

Tab. 3-2-3-2 presents the summary of integration and enthalpy of each PO block for the

samples of toluene and the 3.6 mm F108 solution. Toluene enhances the integration of

the 3.6 mm F108 solution, and the growing area of thermal peaks is proportional to the

increasing toluene.

The solubility of toulene in water is lower than 1-Hexanol. If the functional group of

Toluene from CH3- changes to OH-, the solubility will be increased. The solubility of

Phenol in water is around 84 g/L equal to 975 mm [77]. In the presence of phenol shifts

the thermal peaks of triblock copolymer solution to low temperature [78].

Toluene and the 7.0 mm F108 solution

In this case, 3.6 mm F108 is increased to 7.0 mm and we studied toluene concentrations

of 0 to 40 mm in the temperature range of 0 to 60oC at scanning rate of 0.5oC/min. by

DSC heating and cooling cycles.

010 20 30 40 50 60

-400

-300

-200

-100

100

200 010 20 30 40 50 60

-200

-100

100

200

300

400

T/ oC

uJ/ s

Toluene and 7 mm F108solution at 0.5 oC/min.

Toluene / mm

0 mm

5 mm

10 mm

20 mm

40 mm

Fig. 3-2-3-2a and 2b: Toluene in 7.0 mm F108 as a function of temperature in heating (2a)

and cooling (2b) processes

The thermal peaks of the 7.0 mm F108 solution shift to low temperatures in the presence

of toluene, which are shown in Fig. 3-2-3-2a and 2b. The shifted peaks are proportional to

the concentration of toluene. High amounts of Toluene, like 20 mm and 40 mm, enhanced

not only the peaks’ position, but also the deformed thermal peaks’, especially in the

heating process. Like other additives, e.g. Geraniol, the deformed peaks all occur under

room temperature. For the most part, F108 copolymers form unimer phases at lower a

temperature, which leads to reduced solubility capacity space for more additives.

Tab.3-2-3-3: Tonset and Tpeak of Toluene and 7.0 mmF108 in thermal process

Toluene in 7.0 mm F108 solution at scan rate of 0.5 oC/min

Heating process

Cooling process

1-Hexanol/ mm

T onset

T peak

T onset

T peak

23.6

27.1

37.5

25.6

5.0

23.7

27.3

34.5

25.7

21.6

26.8

34.3

25.1

18.1

26.2

33.6

24.5

14.6

25.0

33.3

23.2

Tab. 3-2-3-3 summarizes the values of Tonset and Tpeak for samples of toluene in 7 mm F108

in both processes. Both temperatures are decreased in the presence of Toluene. The

decreasing temperature is proportional to the concentration of Toluene. The 7mm F108

solution results lower Tonset and Tpeak than the 3.6 mm F108 solution. Toluene is helpful to

induce the decreasing values of Tonset and Tpeak in both thermal processes.

Tab. 3-2-3-4: Integration Q and ΔH(PO) of Toluene and 7.0 mm F108 solution in thermal

process

Integration Q and ΔH(PO) of 7.0 mm F108 with the variation of Toluene/ mm at 0.5 oC/ min

Integration Q/mJ

ΔH(PO)/ kJmol-1

Toluene/ mm

Heating

Cooling

Heating

Cooling

386.3

372.1

4.10

3.95

5.0

384.1

370.0

4.08

3.93

10.0

381.7

371.4

4.05

3.94

20.0

400.6

378.0

4.25

4.01

40.0

429.6

416.4

4.56

4.42

The results of integration Q and enthalpy ΔH(PO) have been shown in Tab. 3-2-3-4. The

results of integration increase in the presence of toluene and are dependent on

concentration in both thermal processes. It means that the transition state of micellization

has been influenced with the addition of Toluene. The enthalpy of each PO block results in

increasing amounts of toluene in the 7.0 mm F108 solution.

3-2-4 Influence of apolar oil in F108 solution

020 40 60 80 100

T/ oC

1-Hexanol / mm

3.6 mm F108

T onset

T peak

7.0 mm F108

T onset

T peak

Fig. 3-2-4-1: Values of Tpeak and Tonset of in 3.6 mm and 7.0 mm F108 solutions in the

presence of 1-Hexanol

Fig. 3-2-4-1 summarizes the values of Tpeak and Tonset for two fixed concentration of F108

solution as a function of 1-Hexanol. The results show that increasing amounts of 1-

Hexanol lead to lower temperatures of Tpeak and Tonset. Both Tpeak and Tonset decrease

nearly as linear functions with increased concentrations and Tonset is approximately parallel

to Tpeak. The results of Tonset and Tpeak for 7.0 mm F108 are lower than 3.6 mm F108, but

parallel to them, because the decreasing temperature is proportional to the concentration

of F108. The cmt values of F108 were approximately a linear function of the polymer

concentration below 10 wt.% [79]. Tonset and Tpeak can be used as an index to anticipate the

micelle phases and to determine the values of critical micelle temperature [78, 80-82].

Normally the Tonset is defined as cmt. When the temperature is below its cmt at a fixed

concentration, polymer chains in water exist as unimers. The micellization begins at cmt

and ends at Toff, which is the temperature at the end of the thermal peak. In the region

between cmt and Toff, polymer chains exist as unimers, micelles, or both. Above Toff, all the

micelles would have been formed, but this does not necessarily mean that there are no

free F108 chains in the aqueous solution. However, no significant heat is detected above

Toff [68].

020 40 60 80 100

dT/dcoil

=0.612 oCmm-1

1-Hexanol

Geraniol

Toluene

T/ oC

Oil/ mm

The polar oil in 3.6 mm F108 solution in heating process

dT/dcoil

=0.223 oCmm-1

Fig. 3-2-4-2: Reduced Tpeak of 1-Hexanol, Geraniol and Toluene as a function of

concentration

The △T of 3.6 mm F108 is presented in Fig. 3-2-4-2 as a function of concentration for oil

which is 1-Hexanol, Geraniol and Toluene. The value △T comes from the difference

between Tpeak of pure 3.6 mm F108 and Tpeak of 3.6 mm F108 in the presence of oil. The

curve shows that each of them induces the decreasing values of Tpeak and is proportional

to the amounts of oils. Forming micellization is mainly controlled by the length of the

hydrophobic part of PO blocks because of dehydration. The oils selected in this

experiment results effectively in lowering the peak temperature. Geraniol results reducing

Tpeak values with increasing concentration. The curve line of Geraniol grows as linear

function and results highest slope d(△T/Coil) = 0.612 oCmm-1 of other oils. Geraniol more

effectively lowers the temperature of the dehydration process of F108 than than do 1-

Hexanol and toluene. This process characterizes an appearance of micellization formation.

It reduced 0.612 oC per mmol. The curves of 1-Hexanol and toluene appear nearly equal

in slope d(△T/Coil) = 0.223 oCmm-1; they are able to be effective to lower the critical

micelle temperature as well. 1-Hexanol can be dissolved more than Geraniol and Toluene

in F108 aqueous solution. Per mmol 1-Hexanol reduced only 0.223oC for 3.6 mm F108

solution, but high solubility capacity can overcome this disadvantage to reach the lowest

reduced temperature purpose. Toluene has been shown to effectively lower peak

temperature, but the solubility in the F108 solution is lower than 1-Hexanol.

020 40 60 80 100

3,5

4,0

4,5

5,0

5,5

6,0

6,5 dHPO/dcoil

=0.075 KJmol-1mm-1

H(PO)/ KJmol-1

Oil/ mm

1-Hexanol

Geraniol

Toluene

The polar oil in 3.6 mm F108 in cooling process

dHPO/dcoil

=0.029 KJmol-1mm-1

Fig. 3-2-4-3: Enthalpy ΔH(PO) of 1-Hexanol, geraniol and toluene in 3.6 mm F108 as a function

of concentration

The endothermic and exothermic reactions, which are due to the dehydration and

hydration of PPO, are enhanced in the presence of polar oil. Fig. 3-2-4-3 summarizes the

enthalpy △H(PO) as a function of the concentration for the different oils for the cooling

process. The enthalpy △H(PO) is obtained from the thermal phase transition of the F108

solution. In the presence of oil, it is helpful to enhance the enthalpy of F108, although the

oils perform no thermal reaction alone in solution. Enthalpy of each PO increases directly

proportional to the amounts of oil added with a slope d(△HPO/coil) = 0.029 kJmol-1mm-1.

This linearity still works well for 1-Hexanol for the highest concentration of 100 mm, which

indicates that the solubility capacity of 3.6 mm F108 for 1-Hexanol is still not reached. The

other oils Geraniol and Toluene have a lower solubility capacity than 1-Hexanol. The

enthalpy of △H(PO) is increasing in the presence of Geraniol and Toluene in a similar

fashion and the slope d(△HPO/coil) = 0.075 kJmol-1mm-1. Geraniol results in highest

efficiency for the thermal reaction of PPO. The additional enthalpy is increased

proportional to the concentration. Other oils, like toluene and 1-Hexanol in the F108

solution, produce energy lower than geraniol. Because the highest solubility capacity of

other oils, 1-Hexanol can help F108 produce more energy in solutions by an increase of at

least more than 60 mm.

3-3 Primary alcolhols (Ethanol, 1-Butanol, 1-Hexanol and 1-Octanol)

and the F108 solution

In this part different primary alcohols were selected as co-surfactants in the 3.6 mm F108

solution. The solubility capacity of those four alcohols is found commonly on information

platforms, like Google. At 20oC, ethanol is soluble arbitrarily in water and 1-Butanol is

soluble around 7.9 g/L in water, 1-Hexanol is 5.9 g/L and 1-Octanol is 0.30 mg/L. Their

solubility in water is decreased in relation to the chain length. The phase behaviour is all

homogeneous at amounts of 30 mmol in the presence of 3.6 mm F108 solution.

010 20 30 40 50 60

-200

-100

100 010 20 30 40 50 60

-100

100

200

300

uJ/ s

30 mm Alcohol

without

Ethanol

Buthanol

Hexanol

Octanol

T/ oC

Alcohol and 3.6 mm F108 at 0.5 oC/min.

Fig. 3-3-1a and 1b: Alcohol in 3.6 mm F108 at scan rate of 0.5oC/min. in heating (1a) and

cooling (1b) processes

Fig. 3-3-1a and 1b describe thermal processes for four different primary alcohols at the

same chemical amounts of 30 mm in the 3.6 mm F108 solution, respectively. The thermal

peaks of 30 mm ethanol are observed that no movements shift to low temperature. For the

peaks of 30 mm 1-Butanol increases indistinctly compare with the pure 3.6 mm F108

solution. Both are relatively polarer than 1-Hexanol and 1-Octanol. 30 mm Ethanol and 1-

Butanol are soluble in pure water, so they have no influence, or maybe unobviously, on

the dehydration process of F108 solution. The 30 mm 1-Hexanol is independently soluble

in water in the absence of F108 as well. However, the thermal peaks shift to lower

temperatures in the presence of 1-Hexanol. The 30 mm 1-Octanol results in the lowest

peak temperature in comparison to other 30 mm alcohols. Deformed thermal peaks

appear in the presence of 1-Octanol at low temperatures in the thermal processes. The

samples of 30 mm 1-Octanol have been measured Rh with decreasing temperature from

25 to 15oC. The phase behaviour becomes a turbid solution when the temperature goes

down to 16oC. The solubility capacity of 30 mmole octanol is limited under 16oC in

uncompleted micelle phases of 3.6 mm F108.

Tab.3-3-1: Tonset and Tpeak of alcohols and 3.6 mmF108 in thermal process

30 mm alcohol in 3.6 mm F108 solution at scan rate of 0.5 oC/min

Heating process

Cooling process

Alcohol

T onset

T peak

T onset

T peak

26.6

31.1

39.1

29.6

Ethanol

27.1

31.1

39.0

29.2

1-Butanol

25.5

30.7

38.4

29.2

1-Hexanol

18.3

24.6

33.7

23.1

1-Octanol

13.2

16.4

25.6

12.8

Tab. 3-3-1 summarizes the Tonset and Tpeak of 30 mm primary alcohol in the 3.6 mm F108

solution in heating and cooling processes. The presence of Ethanol does not influence

Tpeak, but the Tonset is increased. In the presence of 1-Butanol, 1-Hexanol and 1-Octanol, it

results in decreasing values of Tonset and Tpeak for the 3.6 mm F108 solution and is

proportional to the alkyl chain length. 1-Butanol, 1-Hexanol and 1-Octanol are effective for

F108 in lowering the temperature of the dehydration process. 1-Octanol shows the most

efficiency in lowering the critical micelle temperature of the 3.6 mm F108 solution.

Tab.3-3-2: Integration Q and ΔH(PO) of alcohols and 3.6 mm F108 solution in thermal process

Integration Q and ΔH(PO) of 3.6 mm F108 with the 30 mm alcohol at 0.5 oC/ min

Integration Q/mJ

ΔH(PO)/ kJmol-1

Heating

Cooling

Heating

Cooling

No alcohol

194.2

189.1

3.79

3.70

Ethanol

189.9

183.9

3.71

3.59

1-Butanol

195.6

191.2

3.82

3.74

1-Hexanol

237.9

226.1

4.65

4.42

1-Octanol

277.5

253.5

5.42

4.95

Tab. 3-3-2 summarizes the results of integration Q and enthalpy ΔH(PO) for the 3.6 mm

F108 solution in the presence of primary alcohols, respectively. The integration Q and

enthalpy ΔH(PO) are decreased in the presence of Ethanol. This phenomenon is similar to

the other publication. The presence of Ethanol decreases the thermal peaks of triblock

copolymer solution and the presence of Methanol decreases as well [83]. In the presence

of 1-Butanol, 1-Hexanol and 1-Octanol result integration Q and enthalpy ΔH(PO)

increasingly. At the same chemical amounts of alcohols, the increasing enthalpy is related

to chain length. 1-Octanol shows the highest effiency in lowering the cmt and increasing

the entropy on each PO block in comparison to other primary alcohols.

Four different primary alcohols with the same chemical amounts are mixed in the 3.6 mm

F108 solution respectively. The thermal peaks of 30 mm ethanol result in decreasing

integration and the 30 mm 1-Butanol is increased a little bit. The length of the alkyl chain

influences the polarity of alcohols. Short alkyl chains like Ethanol tend toward polar

molecules and are soluble easily in water. Methanol and Ethanol perform the water-

structure-breakers prevent the self-hydration of water, resulting in increased polymer

solubility [83]. When the longer chain are selected such as 1-Butanol, 1-Hexanol and 1-

Octanol, they could exist in the water environment, but to a limited extent. In the addition

of longer chain alcohols is effective on decreasing cmt. They perform a water-structure-

maker promoting the self-hydration of water by favourable interaction between longer

chain alcohol and water resulting in the exclusion of copolymer in the solvent region [83].

The longer chain alcohols favour the aggregated form of the copolymer [84]. The solubility

does not decrease as a linear function because ethanol dissolves at high solubility in

water and 1-Octanol can almost not be dissolved in water. The phase behaviour of 30 mm

1-Octanol in the 3.6 mm F108 solution is clear, transparent and homogeneous, but they

are all prepared at room temperature. There are some DSC thermal peaks, which appear

deformed, at low temperatures. This tells us that the solubility is reduced and limited for oil

and caused by the uncomplete micelle formation. In the cooling process the exothermic

peak of 30 mm 1-Octanol becomes deformed and the reason is the solubility capacity of

hydrophobic blocks being reduced dependent on temperature as well. 30 mm 1-Hexanol

is observed no deformed thermal peaks, because it is still soluble in water at this quantity

in the absence of F108. In the 3.6 mm F108 aqueous solution the solubility capacity of 1-

Hexanol is tested personally at at least 150 mmol.

0 2 4 6 8

-2

-1,0

-0,5

0,0

0,5

1,0

1,5

2,0

dHPO/dCH2

=0.40

dT/dCH2

=3.08

HPO/ KJmol-1

Tonset/ oC

HO-(CH2) n

T/ oC

Alcohol and 3.6 mm F108 solution

PO Enthalpy/ KJmol-1

Fig.3-3-2: ΔTonset and Enthalpy ΔH(PO) of primay alcohol in 3.6 mm F108 as a function of

carbon values

Fig. 3-3-2 summarizes ΔTonset and Enthalpy ΔΔH(PO) as a function of carbon chain value. In

the presence of ethanol, where the carbon chain value is at 2, there appear to be no

significant influences on the F108 solution. The influence is a little clear when the CH2 is

increased to 4. Then it is increased as a linear function when the CH2 keeps increasing. If

alcohols have to be chosen as co-surfactants, 1-Butanol is the bottom line for influencing

the dehydration of F108, because ethanol is not effective. 1-Octanol is the most efficent

alcohol as a co-surfactant for improving the dehydration process of F108. The slope

d(△T/CH2)=3.08oC means that they are effective in lowering the temperature for each

extra CH2 on average and the slope d(△HPO/CH2)=0.40 KJmol-1 indicates the

enhancement. The enthalpy of PO is effective dependent of carbon chain length of

alcohols as well.

Results of DLS measurements

Each of the 30 mm alcohols was measured by DLS from 20oC to 40oC to analyse the size

modification of the dehydration process for the 3.6 mm F108 solution.

20 25 30 35 40

Hydrodynamic radius Rh of 30 mm alcohol in 3,6 mm F108 solution

Rh/ nm

T/ oC

No alcohol

Ethanol

1-Butanol

1-Hexanol

1-Octanol

Fig. 3-3-3: Resuls of Rh for primary alcohols as a function of temperature

Fig. 3-3-3 shows the results of the hydrodynamic radius of primary alcohol in 3.6 mm F108

as a function of temperature. At 25 oC, it shows the radius of 1-Hexanol and 1-Octanol as

being higher than the radius of ethanol and 1-Butanol. The results of DSC measurements

(see Fig.3-3-1a and 1b) have been observed that the endothermic and exothermic peaks

of 3.6 mm F108 shift obviously to lower temperatures in the presence of 1-Hexanol and 1-

Octanol, respectively. In the presence of 30 mm 1-Hexanol, the 3.6 mm F108 holds the

maximal hydrodynamic radius Rh at 25oC, it starts to reduce when the temperature

increases. In this Fig. 3-3-3 the highest value of Rh for 3.6 mm F108 in the presence of 1-

Octanol is at 20oC, because later this sample is measured at lower temperatures (see Fig.

3-3-8). The maximal Rh of 1-Hexanol and 1-Octanol for 3.6 mm F108, respectively, is

close to their peak temperature. A high intensity of thermal peaks of F108 solution results

in the maximum of Rh. In the presence of ethanol and 1-Butanol, the maximal Rh at 30oC

appears and is close to the results of their peak temperature. Their thermal peaks of 3.6

mm F108 in the presence of ethanol have an influence on lowering the temperature and,

in the presence of 1-Butanol, shift a little. If all the samples are measured continually at

35oC and 40oC, the Rh results decreasingly. They decrease until the constant stable state.

There is short Rh around 3 to 4 nm detected at 25oC for the pure 3.6 mm F108 solution. In

the presence of ethanol and 1-Butanol short Rh is observed as well. They are the size of

unimer phases. The Rh of unimer F108 is enhanced in the presence of Ethanol and 1-

Butanol, although it does not increase much. Ethanol and 1-Butanol are at high solubility

capacity in water, the 30 mmol amounts have an extremely low influence on lowering

temperature of dehydration processes of F108. In the presence of both alcohols, the

similar cmt value with no alcohol F108 solution results. Therefore, due to high solubility in

water, the short chain length alcohol, like Ethanol and 1-Butanol, has almost no influence

on the decreasing temperature of the dehydration effect for the F108 solution. If the Rh of

F108 is measured at 30oC, the results appear only slightly increasingly in the presence of

ethanol and 1-Butanol. The results are not demonstrative to prove the existence of ethanol

and butanol in the micelle phases of F108. In other words, the long chain length alcohol

like 1-Hexanol and 1-Octanol, compared with ethanol and 1-Butanol, have low solubility in

water. Their solubility capacity is related to the length number of (CH2)n and is

proportionally inverse. 1-Hexanol at the amount of 30 mmol is still homogenous in water;

the solubility capacity of 1-Hexanol is 5.9 g/L and is equal to 57 mm in water, so the

sample of 30 mm 1-Hexanol is unnecessary to exist in the F108. However the maximal Rh

of 3.6 mm F108 is detected at 25oC in the presence of 1-Hexanol. This maximum value

occurs at the temperature lower than no alcohol F108 solution. 1-Hexanol induces the

temperature of dehydration processes of the F108 solution. This phenomenon is more

obvious in the presence of 1-Octanol, because the solubility capacity is extremely low –

around 0.30 mg/ L in water. It is equal with the concentration in 2.3x10-3 mm. However the

phase behaviour of 30 mm 1-Octanol is homogeneous in the 3.6 mm F108 solution at

room temperature. The maximal Rh of F108 is found in Fig. 3-3-3 in the presence of 1-

Octanol at 20oC. At fixed concentrations of F108 under their cmt, mostly unimer phases

appear in the solution. The space of unimers for hydrophobic parts is smaller than in the

micelle phase, even the hydrophobic part of PO blocks prefers to be less hydrophobic.

Therefore the oil wants to be solubilized in the solution, especially at low temperatures.

The oil, like 1-Hexanol or 1-Octanol, forces each F108 coplymer aggregate to let its critical

micelle temperature be reached in advanced. At the same time the activation energy

decreases in the presence of oil. For this reason, the large space of hydrophobic area is

formed for the hardly soluble water of oil.

20 25 30 35 40

Rh/ nm

T/ oC

Ethanol/ mm

0 mm

30 mm

100 mm

200 mm

500 mm

Hydrodynamic radius Rh of Ethanol in 3,6 mm F108 solution

Fig. 3-3-4: Hydrodynamic radius Rh of the variable concentration of ethanol in the 3.6 mm

F108 solution as a function of temperature

Fig. 3-3-4 summarizes the Rh of 3.6 mm F108 in the presence of Ethanol as function of

temperature. Compared with the same chemical amounts of alcohols like 1-Hexanol and

1-Octanol (see Fig. 3-3-1 and 3), ethanol induces no surprising phenomenon at fixed

concentrations of F108. The amounts of ethanol keeps increasing to 100 mm, 200 mm

and 500 mm in order to analyse the influence on the micelle phases of F108 by means of

DLS. They were measured dependent on temperature and there appears to be no

significant hydrodynamic radius Rh under cmt. The Rh of 100 mm ethanol at 25oC is

debatable because the Rh of 200 mm and 500 mm result relatively smaller. It is hard to

make a conclusion that with increasing amounts of ethanol it would induce the

aggregation of F108. The hydrodynamic radius Rh is dependent on temperature and

solvent properties like viscosity (see part 2-2). The solvent is water; the viscosity of water

is dependent on temperature. It is 1.002 cp at 20oC and decreases with increasing

temperature. The amounts of ethanol are at high value in 3.6 mm F108, the 500 mmol

Ethanol occupies around 2.5 % of total solution. Although the density of Ethanol, which is

0.79 g/cm3 at 20oC, is lower than water. The viscosity of pure Ethanol is 1.200 cp at 20oC,

and decreases with high temperature as well. Ethanol with hydroxyl (-OH) group and

water are polar molecules. Another possibility is that the hydrogen bond is formed

between the hydrogen of the -OH group of ethanol and the oxygen of the water molecule.

This could result in that mixtures of ethanol and water at different temperatures show a

wide range of dielectric constants, viscosities, densities and a high degree of hydrogen

bonding effects. The hydrophobic effect between ethanol, water and the F108 copymer is

considered also. If we want to take the viscosity mixture of water and ethanol for this

experiment into consideration, the value can be calculated in accordance with the

equation as follows:

Water

Water 









(3-3-1)

The viscositymixture η of water and ethanol is related to the density ρ and flowing time t.

The samples are directly measurable by the ubbelohde viscosimeter. If the temperature is

increased to 35oC, the Rh of the samples at the highest value decreases to 10 nm. When

the temperature keeps increasing to 40oC, the Rh of them keeps decreasing. The high

temperature leads the F108 copolymer to become more hydrophobic in solution, so water

or ethanol partially would be dispelled from PO and even EO blocks, letting the

hydrophobic blocks aggregate more condensable. In the presence of high amounts of

ethanol, no significant influence has an affect on the increasing size of aggregation of the

F108 solution.

20 25 30 35 40

0,00003

0,00006

0,00009

0,00012

0,00015

0,00018

0,00021

Ethanol in 3.6 mm F108 solution

Ethanol

0 mm

30 mm

100 mm

200 mm

500 mm

T/ oC

R/ cm-1

Fig. 3-3-5: Intensity of variable concentrations of ethanol in the 3.6 mm F108 solution as a

function of temperature

The scattering intensity I in Hz fluctuates as a function of measuring time. It can be

translated into the Rayleigh ratio Rθ in cm-1 with a mathematical equation. The values Rθ

come from

Toluene

Sample

Toluene

Sample





(3-3-2)

The scattering intensity Isample and IToluene is obtained by DLS measurements and Rθ from

toluene is constant at the value 1.4 * 10-5 cm-1. It is also the reference to characterize the

scattering intensity at each scattering angle θ. The results of Rθ of ethanol for increasing

amounts in 3.6 mm F108 respectively is presented as a function of temperature in Fig. 3-

3-5. The fluctuation is sensitive to the size of particles in the solution. At 20oC the lowest

intensity of ethanol results, which means they appear as mostly unimer phases in the

solution. In the presence of ethanol, the Rθ of intensity enhances even though they are still

as unimers in the solution. The Rayleigh ratio Rθ is obtained from theory of Static light

scattering.

When temperature is on the increase, the F108 copolymer tends to dehydrate and

translate with high probability to the micelle phases, which results high values of Rθ. To

compare the Result in Fig. 3-3-4, the Rh of them appear the highest values at 30oC,

because ethanol has nearly no influence on lowering the cmt values of F108. If the

temperature keeps going up, the Rh remain decreasing. On the contrary, the intensity at

30oC is not the maximum, it keep increasing when the temperature warms to 35oC and

40oC. The intensity, due to the density of each dehydrated F108, leads to the size of

aggregation reduced. However the intensity is not proportional with the concentration of

ethanol. The sample of 30 mm of ethanol results the highest intensity than other samples.

When the concentration of ethanol increases to 100 mm, 200 mm and 500 mm, they

result in the decreasing values of Rθ proportionally over 30oC.

Analysis of regularized fit

0,1 1 10 100 1000

14 0 o C

R h / n m

Int.

0 m m H e x a n o l i n 3 . 6 m m F 1 0 8

13 5 o C

13 0 o C

12 5 o C

12 0 o C

0,1 1 10 100 1000

2 0

3 0

4 0

R h / n m

3 0 m m H e x a n o l i n 3 . 6 m m F 1 0 8

2 5

3 5

Fig. 3-3-6: Results of size distribution analysed by regularized fit for 30 mm 1-Hexanol in 3.6

mm F108 from 20oC to 40oC

Fig. 3-3-6 shows the results of size distributions by DLS measurements for samples of 0

mm and 30 mm Hexanol in fixed concentration of 3.6 mm F108 solution. Both samples

were measured with for temperatures from 20oC to 40oC and analysed with the

regularized fit model. Left curve from Fig. 3-3-6 is the F108 solution in the presence of 0

mm 1-Hexanol from 20 to 40oC. It appears as one peak at 20oC and peak position is at

around 2.44 nm. The hydrodynamic radius Rh for 2.44 nm is close to the gyrarion radius

Rg 2.31 nm that is analyzed by SANS. It implies that there are no micelle phases for the

given concentration of 1-Hexanol in the F108 solution at this temperature. They exist as

almost unimer phases in the solution. When the temperature keeps increasing, there is

another peak that seems to appear and is located between 10 nm to 100 nm. At 30oC, this

peak appears obviously to be seen. Meanwhile, the first peak at 2.44 nm becomes weak

as the temperature goes up higher. Unimer phases could translate into micelle phases

because of dehydration of PO blocks, so the second peak grows. Moreover it tends to

shift to the short Rh position around 10 nm when the temperature increases to 40oC.

Phase transition of the dehydration process of PPO influences the size of aggregation. PO

blocks are dependent on temperature and they gain a hydrophobic appearance with

increasing temperature.

Because hydrophilic appearance from PO blocks disappears gradually, it results as Rh

reduces. As the temperature continues increasing, the hydrophobic character of PO is

enhanced at the same as the hydrophilic character PO is reduced. The reduced

hydrophilic phenomenon leads to the exclusion of hydrophilic solution from the

hydrophobic parts of PPO.

Fig. 3-3-7: Model of triblock copolymer F108 in aqueous solution as a function of

temperature

Fig. 3-3-7 is an image model for F108 in the aqueous solution at different temperatures to

interpret the process of phase transition from unimer to complete micelle phases in detail.

The triblock copolymer F108 can be soluble in water as unimer phases at low

temperatures, like the left curve. The increased temperature leads to the PO blocks of

F108 being dehydrated and the dehydrated PO blocks form aggregates as irregular

shapes in the solution at the beginning (middle curve). During the process of phase

transition they contain hydrophilic appearance, so PO blocks and water are coexistent in

the core and appear as huge swelling particles. The model in the middle presents the

F108 form aggregation like micelle phases. At this moment they have already gone over

their cmt, but the parts of PPO exist still with water. If the temperature keeps increasing,

the hydrophilic character of PPO decreases and pushes the remaining water out of the

hydrophobic part. Particles for the hydrophobic parts become more densely and result in a

decreasing Rh.

Fig. 3-3-6 (at the right side) shows the results of size distribution as a function of

temperature in the presence of 30 mmol 1-Hexanol. Compared with the pure F108

solution, the curve appears as two peaks at 20oC. One is for unimer phase of F108 and

the other is micelle phase. The presence of 1-Hexanol is effective in lowering the

temperature of the dehydration process for the F108 solution. This phenomenon

corresponds with the results of the Nano DSC.

△T

15 20 25 30 35 40

100

1000

Rh/ nm

T/ oC

Simple Fit

Regularized Fit

30 mm Octanol in 3,6 mm F108 solution

Fig. 3-3-8: Hydrodynamic radius Rh of 30 mm 1-Octanol in 3.6 mm F108 analysed by means

of Simple Fit and Regularized Fit as a function of temperature

Fig. 3-3-8 summarizes the hydrodynamic radius Rh of samples containing 30 mm 1-

Octanol in the 3.6 mm F108 solution as a function of temperature. The autocorrelation

function is analysed by the ALV 7004 programme and two methods are used to determine

the Rh. One is the Simple Fit. Only one Rh is obtained by calculation of the model, which

are the size particles mainly in solution. The other calls ALV-Regularized Fit; it presents

not only the Rh but also the percentage of unimer and micelle coplymers. The sample was

measured from -25oC to 15oC because the DSC peak of 30 mm 1-Octanol is obtained at

16.4oC. The results of Rh lead to increases when the temperature goes down. At low

temperature the PO blocks of F108 turn to be hydrophilic relatively and the aggregates

swell because of water. The solubility capacity of 1-Octanol in water is only 0.30 mg/L at

20oC and it is almost insoluble in water [85]. In the presence of 3.6 mm F108, it lets the

solubility of 1-Octanol increase to 3.9 g/L in water homogenous at the same temperature.

Compared with other 30 mm alcohol samples (see Fig. 3-3-1), 30 mm 1-Octanol results in

the lowest peak temperature of other samples. 1-Octanol accelerates the dehydration

process for PO blocks of F108 in order to homogenize in the solution, so the endothermic

and exothermic peaks shift to a low temperature position. 30 mm 1-Octanol starts to turn

turbid slightly at 16oC below the perceptible observation. Emulsions could be formed in

solution. The turbid solution is due to partial unsoluble 1-Octanol and the solubility of

octanol in the F108 solution is reduced when the temperature goes down. Therefore the

turbid solution results to the Rh closed to 100 nm and 1000 nm at 16oC and 15oC,

respectively. The interference from the turbid solution of 30 mm 1-Octanol leads to

inaccuracy of Rh at 15oC and 16oC.

1E-61E-51E-41E-30,01 0,1 1 10 100 100010000100000

-0,05

0,00

0,05

0,10

0,15

0,20

0,25

0,30

0,35

0,1 1 10 100 1000 10000

0,0

0,2

0,4

0,6

0,8

1,0

1E-61E-51E-41E-30,01 0,1 1 10 100 100010000100000

-0,05

0,00

0,05

0,10

0,15

0,20

0,25

0,30

0,35

16 oC

size distribution

16 oC

15 oC

 / ms 0,1 1 10 100 1000 10000

0,0

0,2

0,4

0,6

0,8

1,0

15 oC

Rh /nm

A.U

correlation function

Fig. 3-3-9: Autocorrelations function and size distribution of 30 mm 1-Octanol in 3.6 mm

F108 at 15oC and 16oC

Fig. 3-3-9 presents the curves of the autocorrelation functions and size distribution for the

sample of the F108 solution in the presence of 30 mm 1-Octanol. The sample was

measured at 15oC and 16oC, respectively. At 16oC, the autocorrelation function shows the

first exponential decay at lag time position from 0.01 ms to 0.1 ms. Significant particles are

detected and Rh is 31 nm after the calculation of simple fit. There are three peaks

observed in the curve of size distribution. They are at 33.7 nm. Both of them are

appropriate to micelle size. At 15oC the exponential decay shifts to late position from 0.1 to

0.01 ms.

However the sample is prepared with 220 nm filter 5 times before measurements. The

samples which are measured below their cmt, result somtimes no significant particles in

solution. The results of size distribution appear only one strong peak at huge size position

and the other peaks disappeared. The observation of its phase behaviour is turbid

because the solubility of 30 mmol octanol is over the limited in 3.6 mm F108 solution at

15oC.

3-4 Mixtures of polymer and F108 solution

In this part two kinds of different polymers were selected to be admixed to a fixed

concentration of the F108 solution. One is the homo block polymer PPO, connected

without any EO blocks. PO17 and Mw is around 1000 gmol-1. The chain length of PO17 is

shorter than the hydrophobic part of F108 (PO50). It can be expected to be soluble in the

core of micelle phases when micelles have been formed. Otherwise PPO becomes

increasingly hydrophilic with decreasing temperature. The other polymer is Kollicoat MAE

30 DP. It is a copolymer of methacrylic acid/ethyl acrylate and used as a film-former in the

pharmaceutical industry as well as in the production of enteric coatings or solid dosage

forms. The solubility of Kollicoat MAE 30 DP is freely miscible in water and Kollicoat MAE

retains its milky white appearance when mixed with water.

3-4-1 Homo copolymer PPO and the F108 solution

PPO and the 3.6 mm F108 solution

We studied PPO concentrations of 0 to 20 mm in the presence of the 3.6 mm F108

solution in the temperature range of 0 to 60oC by DSC heating and cooling cycles.

010 20 30 40 50 60

-500

-400

-300

-200

-100

100

010 20 30 40 50 60

-100

100

200

300

400

500

600

PPO and 3.6 mm solution at 0.5 oC/min.

PO17 / mm

0 mm

1.0 mm

3.0 mm

6.0 mm

10 mm

20 mm

uJ/ s

T/ oC

Fig.3-4-1-1a and 1b: DSC curve of PPO in 3.6 mm F108 as a function of temperature in

heating (1a) and cooling (1b) processes

In the presence of homo copolymer PPO shifts no movements of thermal peaks to low

temperatures. The peak intensity increases with the addition of PO blocks in both

processes and is proportional to the concentration. In the heating process for the sample

of 6 mm PPO, a small peak appears close to 47oC and so does the cooling process. If we

increase the PPO to 10 mm, this small additional peak shifts to low temperatures around

40oC. Samples above 6 mm PPO (see Fig. 3-4-1-1) are observed an additional peak at

right side. These additional peaks for the sample of 6, 10 and 20 mm is at 46.4oC, 38.7oC

and 33.2oC respectively. The increasing amounts of PPO shift the additional peak to low

temperature. The sample of 10 mm PPO was put into a constant temperature furnace to

observe the phase behaviour. The temperature was set at 56oC and the sample turns

turbid in the furnace (see Fig. 3-4-1-2). If we take it in the air, it turns clear in a few

seconds. So these additional peaks for 6, 10 and 20 mm PPO should be associated with

the cloud point. Normally the cloud point of a pure 3.6 mm F108 solution is at 107oC and it

is due to the dehydration effect of EO blocks [10]. Apparently the presence of hydrophobic

PPO makes the cloud point substantially lower.

Fig. 3-4-1-2: 10 mm PPO in 3.6 mm F108 at 56oC. It turns clear very quickly at room

temperature.

Compared with other mixtures, like 1-Hexanol, Toluene and Geraniol are in the same fixed

concentration of the F108 solution. They appear transparent at the same high temperature.

The homo copolymer PPO is like oils and hardly soluble in water. It is lipophilic and

contains mostly hydrophobic character. The presence of F108 improves the solubility of

PPO in the solution. The hetergenous phase is observed when the temperature is

increased.

The triblock copolymer F38 contains similar values of hydrophobic blocks equal to PO17.

The chemical structure of F38 is EO42PO16EO42 and the cmt is at around 70 oC at the

amounts 40 mmolkg-1. The ratio and value of EO blocks influence the cmt of triblock

copolymers. For example, three Pluronics, F68, P65, and L62 contain similar numbers of

propylene oxide units around 29 and the numbers of ethylene oxide units are 76, 19 and 8

for F68, P65 and L62, respectively. Under the same weight concentration, the Pluronic

L62 results in the lowest value of the cmt of other pluronics [10]. The clouding point for

other triblock copolymer solution has been influenced by adding of oil [78, 86].

Tab. 3-4-1-1: Tonset and Tpeak of PPO and 3.6 mmF108 in thermal process

PPO in 3.6 mm F108 solution at scan rate of 0.5 oC/min

Heating process

Cooling process

PPO/ mm

T onset

T peak

T onset

T peak

26.6

31.1

39.1

29.6

1.0

26.8

30.9

39.6

29.4

3.0

26.6

30.9

38.5

29.3

6.0

26.0

30.9

39.0

29.4

10.0

26.1

30.8

41.2

29.2

20.0

25.6

30.5

42.8

29.4

Tab. 3-4-1-1 summarizes the values of the Tonset and Tpeak in the presence of PPO in both

thermal processes. Both temperatures result in no significant modification when the

amounts of PPO are increased.

Tab. 3-4-1-2: Integration Q and ΔH(PO) of PPO and 3.6 mm F108 solution in thermal process

Integration Q and ΔH(PO) of 3.6 mm F108 with the variation of PPO/ mm at 0.5 oC/ min

Integration Q/mJ

ΔH(PO)/ kJmol-1

ΔH(PO+PO)/ kJmol-1

PPO/ mm

Heating

Cooling

Heating

Cooling

Heating

Cooling

194.2

189.1

3.79

3.70

3.79

3.70

1.0

204.5

202.8

4.00

3.96

2.98

2.96

3.0

241.3

226.5

4.72

4.43

3.52

3.30

6.0

289.7

268.6

5.66

5.25

4.22

3.92

10.0

434.7

419.8

8.49

8.20

5.42

5.24

20.0

676.3

660.3

13.22

12.90

6.19

6.05

Tab. 3-4-1-2 summarizes the integration and the enthalpy ΔH(PO) in the presence of PPO

in the 3.6 mm F108 solution. The integration of thermal peaks is increasing with increasing

concentration of PPO in the 3.6 mm F108 solution. The homo copolymer PPO is different

from other co-surfactants, like other oils. By adding PPO, it causes large enthalpy when

they turn to dehydrate. Taking the adding PPO into consideration, this table summarizes

another result for entropy ΔH(PO+PO). The enthalpy ΔH(PO+PO) is increases likewise with

increasing amounts of PPO. Therefore in the presence of PPO, it is effective for the F108

solution to increase the entropy energy on each PO unit and to be proportional to the

concentration. By adding a low concentration of PPO, like 1.0 or 3.0 mm, it does not seem

effective; indeed, the entropy decreases.

PPO and 7.0 mm F108

In this part we study the effect of PPO on a 7.0 mm F108 solution. The maximal amounts

of PPO are increased to a 40 mm solution and they are measured by the DSC in thermal

cycles.

010 20 30 40 50 60

-900

-600

-300

300 010 20 30 40 50 60

-300

300

600

900

1200 PPO and 7.0 mm solution at 0.5 oC/min.

T/ oC

uJ/ s

PO17/ mm

0 mm

2 mm

5 mm

10 mm

20 mm

40 mm

Fig. 3-4-1-3a and 3-4-1-3b: DSC curve of PPO in 7.0 mm F108 as a function of temperature in

heating (3a) and cooling (3b) processes

Fig. 3-4-1-3a and 3-4-1-3b show DSC curves of the 7.0 mm F108 solution in the presence

of homo polymer PPO in heating and cooling processes. By adding PPO, it increases the

area of thermal peaks of F108 but the peaks remain fixed at same position. The shifts of

thermal peaks for the 7.0 mm F108 solution result in almost no influence in the presence

of PPO. The additional peak is found first for the sample of 10 mm. It appears around

45.5oC and is very weak in the heating process. The samples for 20 and 40 mm appear

more apparently at 34.3 and 28.5oC. By adding higher concentrations of PPO, it shifts the

additional peak to low temperature.

Tab. 3-4-1-3: Tonset and Tpeak of PPO and 7.0 mmF108 in thermal process

PPO in 7.0 mm F108 solution at scan rate of 0.5 oC/min

Heating process

Cooling process

PPO/ mm

T onset

T peak

T onset

T peak

23.6

27.1

34.0

25.6

2.0

23.4

27.1

34.5

25.4

5.0

23.3

27.2

35.1

25.6

10.0

22.8

27.0

35.3

25.5

20.0

22.0

26.5

37.7

25.1

40.0

21.5

26.3

39.7

24.6

Tab. 3-4-1-3 summarizes the Tonset and Tpeak of the 7.0 mm F108 solution with addition of

the PPO homo copolymer. The results of Tonest decrease slightly in the heating process

with increasing amounts of PPO because of the growing area of the thermal peak. There

is the same appearance for the results of Tonset in the cooling process. They increase

slightly dependent of PPO. The results of Tpeak shift the peaks extremely a bit of

temperature with increasing of PPO.

Tab. 3-4-1-4: Integration Q and ΔH(PO) of PPO and 7.0 mm F108 solution in thermal process

Integration Q and ΔH(PO) of 7.0 mm F108 with the variation of PPO/ mm at 0.5 oC/ min

Integration Q/mJ

ΔH(PO)/ kJmol-1

ΔH(PO+PO)/ kJmol-1

PPO/ mm

Heating

Cooling

Heating

Cooling

Heating

386.3

372.1

4.10

3.95

4.10

3.95

2.0

392.2

390.0

4.17

4.14

3.11

3.10

5.0

435.7

421.5

4.63

4.48

3.45

3.34

10.0

503.8

493.8

5.35

5.24

3.99

3.91

20.0

878.6

854.3

9.33

9.07

5.55

5.40

40.0

1345.6

1297.1

14.29

13.78

6.06

5.84

Tab. 3-4-1-4 presents the results of integration and enthalpy of 7 mm F108 in the

presence of homo polymer PPO. The increasing amounts of PPO lead increasingly to the

intensity of thermal peaks. Moreover, the results of integration Q and ΔH(PO) are

increasing as they should be. Calculating the enthalpy for each PO unit take the units of

homo copolymer PPO into consideration, written as ΔH(PO+PO) , results growing enthalpy

with the increasing of PPO.

010 20 30 40 50 60

H/kJmol-1

Oil/ mmolkg-1

PO17

1-Hexanol

Oils in 3,6 mm F108 solution respectively

Fig. 3-4-1-4: Results of ΔH(PO) as a function of oil concentration in the 3.6 mm F108 solution

Fig. 3-4-1-4 summarizes the results of enthalpy ΔH(PO) as a function of oil concentration

from PO17 and 1-Hexanol in the 3.6 mm F108 solution, respectively. The homo copolymer

PPO shows results of higher entropies than 1-Hexanol for the dehydration process of

F108. If we take ΔH(PO) including PO17 into consideration, they remain increasing

especially at high concentration of PPO (see Tab. 3-4-1-2). The homo polymer PPO,

which is composed of PO blocks same as F108, is able to become dehydrated

independently. 1-Hexanol, as optimal co-surfactant, has no effects on phase transition.

However, it is helpful for increasing the enthalpy of dehydration of PO blocks.

010 20 30 40 50 60

Oils in 3,6 mm F108 solution respectively

Oil/ mmolkg-1

PO17

1-Hexanol

Tpeak/ oC

Fig. 3-4-1-5: Results of Tpeak as a function of oil concentration in the 3.6 mm F108 solution

The peak temperatures of PPO and 1-Hexanol in the 3.6 mm F108 solution are presented

in Fig. 3-4-1-5. The homo copolymer of PO17 leads to no influence on lowering the

temperature of the phase transition peak. By adding PPO it has no effect on decreasing

the cmt values in the 3.6 mm F108 solution, while 1-Hexanol shows high efficiency in

decreasing the peak temperature in the 3.6 mm F108 solution. The solubility capacity of

them in water is limited and can be increased in the presence of the F108 in solution. PPO

is generally not water-soluble at room temperature because of its apolar chemical

structure [87]. Only polymers with low molecular weights have been reported to exhibit

solubility below 18°C [88]. The solubility of 1-Hexanol in water is 5.9 g．L-1 at 20oC is

equal to 60 mm in water. In the presence of 3.6 mm F108, the solubility of 1-Hexanol is

tested to above 150 mm homogeneous at room temperature, but the highest amounts of

1-Hexanol in this diessertation are increased only to 100 mm, which are investigated by

the Nano DSC. The sample of 20 mm 1-Hexanol lowers the peak temperature of 3.6 mm

F108 to 27.9oC in the heating process but the other peak temperature is at 30.8oC for the

sample of 20 mm PPO. The presence of PPO shows low efficiency in lowering the cmt of

the F108 solution.

3-4-2 Kollicoat MAE 30DP and the F108 solution

Kollicoat MAE 30 DP, abbreviated as Kollicoat MAE, is an aqueous dispersion with a solid

content of 30%. It is a milky white and low-viscosity product manufactured by the BASF

Company.

Kollicoat MAE and 3.6 mm F108 solution

010 20 30 40 50 60

-200

-100

100

010 20 30 40 50 60

-100

-50

100

150

200

Kollicoat MAE and 3,6 mm F108 solution at 0,5 oC/min.

uJ/s

T/oC

Kollicoat MAE

0 %

0.5 %

1.0 %

2.0 %

5.0 %

10.0 %

Fig. 3-4-2-1a and 3-4-2-1b: Kollicoat MAE in 3.6 mm F108 as a function of temperature in

heating (1a) and cooling (1b) processes

Fig. 3-4-2-1a and 3-4-2-1b show the results of the thermal behaviour of 3.6 mm F108 in

the presence of Kollicoat MAE in both processes. The maximal thermal peaks are

observed for the pure F108 solution in the absence of Kollicoat MAE. The intensity of

phase transition peaks of F108 decreases in the presence of Kollicoat MAE. This

appearance is similar to the presence of Methanol and Ethanol.* In other words, the

dehydration process of F108 disappears in the presence of Kollicoat MAE. The samples of

5% and 10% show no significant peaks in either process.

Tab. 3-4-2-1: Tonset and Tpeak of Kollicoat MAE and 3.6 mmF108 in thermal process

Kollicoat MAE in 3.6 mm F108 solution at scan rate of 0.5 oC/min

Heating process

Cooling process

K. MAE/ wt. %

T onset

T peak

T onset

T peak

26.6

31.1

39.1

29.6

0.5

27.5

32.4

40.1

30.9

1.0

27.9

33.8

41.1

29.2/33.4

2.0

27.8

33.9

43.6

30.1

5.0

10.0

Table 3-4-2-1 summarizes the thermal behaviour of Tonset and Tpaek values for the 3.6 mm

F108 solution in the presence of Kollicoat MAE. The temperatures of Tonset and Tpeak result

in no decreasing values when the amounts of Kollicoat MAE are increasing. It results in

both temperatures slightly increasing in the presence of Kollicoat MAE. The absence of

Kollicoat MAE results in the lowest temperature of onset and peak in this part. It indicates

that Kollicoat MAE appears to have no influence on lowering the temperature of

dehydration of the F108 solution.

Tab. 3-4-2-2: Integration Q and ΔH(PO) of Kollicoat MAE and 3.6 mm F108 solution in thermal

process

Integration Q and ΔH(PO) of 3.6 mm F108 with the variation of Kollicoat MAE/ % at 0.5 oC/ min

Integration Q/mJ

ΔH(PO)/ kJmol-1

K. MAE/ wt. %

Heating

Cooling

Heating

Cooling

194.2

189.1

3.8

3.7

0.5

140.2

133.1

2.7

2.6

1.0

102.7

95.2

2.0

1.9

2.0

59.2

52.1

1.2

1.0

5.0

10.0

Tab. 3-4-2-2 organizes the results of integration area and enthalpy pro PO block for the

samples of increasing Kollicoat MAE in the 3.6 mm F108 solution, respectively. Fig. 3-4-2-

1 shows the decrease of peak intensity, so the results of integration area are reduced in

the presence of Kollicoat MAE. The enthalpy of ΔH(PO) is also decreased with increasing

amounts of Kollicoat MAE. In the presence of Kollicoat MAE results in no effect on

increasing the energy of phase transition of F108, like polar oils and PPO, but results in

decreased enthalpy. However, Kollicoat MAE acts as a water-structure –breaker that

prevents self-hydration of water to increase the solubility of copolymer [78].

Viscosity

The viscosity of the 3.6 mm F108 solution in the presence of Kollicoat MAE was

measured by means of capillary viscosimeter, which the type of Ic and 0a were selected in

this experiment.

0 2 4 6 8 10

Viscosity of Kollicoat MAE at 25 oC

in H2O

in F108

in F108 with 1N NaOH

original PH values in F108

with 1 N NaoH

Kollicoat MAE/ wt.%

/ mm2s-1

Fig. 3-4-2-2: Results of viscosity and PH values as a function of Kollicoat MAE in wt.%

Fig. 3-4-2-2 presents results of viscosity as function of Kollicoat MAE. Each of them is

soluble in solution under the different condition and was measured at 25 oC. When

Kollicoat MAE is soluble in water, induces not much. Because the viscosity of water is

0.890 mm2s-1, in the presence of Kollicoat MAE increases to 0.903 mm2s-1. By adding

Kollicoat MAE increases the viscosity of F108 solution, meanwhile the PH of F108

solution decreases. When the samples are deprotonated with 1 N NaOH and control the

PH around 6, the adhesive property becomes amplified more apparently especially by

adding high amounts of Kollicoat MAE.

4. Effect of copolymer addition to the stability and permeability of

Phospholipid and Diesterquat (CR3099) vesicles

In this chapter we discuss the effect of different copolymers on the properties of

phospholipic and diesterquat vesicles, with a particular emphasis on their stability and the

permeability of their bilayers. Phospholipids, which are the major components of the cell

membrane, form the bilayer structure in solution. They contain a phosphate head group as

the hydrophilic part and two hydrophobic tails and normally form mutilamellar vesicles in

aqueous solutions. The other chemical compound CR 3099 (chemical formula given in

Tab. 5) is a disesterquat based on oleic acid, which forms a relatively big vesicle (ca. 400

nm in diameter) in aqueous solutions at a concentration of 0.5%. These vesicle

dispersions with different amounts of different copolymers were added in order to see how

they affect the bilayer properties.

4-1 Phospholipids solution

In this part DMPC at concentrations of 0.1 and 0.2 wt.% is used mostly to analyze the

phase behaviour, stability of unilamellar vesicles, permeability and conductivity.

4-1-1. Phase behaviour

Fig. 4-1-1-1: 0.1 wt.% DMPC solution, no extrusion (left), after just extrusion with 100 nm

polycarbonate filter, extruded for a long time

The phase behaviour of 0.1 wt. % DMPC presents turbid and heterogeneous aqueous

solution. Staying quietly for one day, sediment appears at the bottom of the bottle. This

could be due to collapsed multilamellar or unilamellar vesicles of different sizes.

Multilamellar vesicles are rather large and their diameter is several μm. The advantage of

these vesicles is that they consist of a more or less large number of bilayers arranged in

subsequent shells and are characterized by a high degree of cooperativity in comparison

with unilamellar liposomes. They are therefore not suitable in experimental arrangements

that do not allow the stirring of the solution. In contrast, unilamellar phospholipic vesicles

can be prepared by extrusion methods at the size of 100 nm to be suitably analysed by

the scattering method. After just extrusion, the sample is homogenous and almost

transparent, waiting for a period of time; sediments of lipids can be observed and

sometimes suspended as well. Other DMPC solutions in the presence of additives, like

copolymer or DHPC, appear with the same phase behaviour.

4-1-2 Phase transition [36]

Gel-to-liquid crystal phase transitions characteristic of lipid bilayer structures can be

observed by thermal techniques. At a given temperature, phospholipids go from a less

ordered liquid crystalline phase to a more ordered gel phase when the temperature

decreases. The peak values Tm and Tc for the heating and cooling process, respectively,

were determined by the Nano DSC.

010 20 30 40 50 60

-80

-40

120

160

J/s

T/ oC

Scan rate at 0.2oC/min.

Heating process

cooling process

unextruded 0.1% DMPC aqueous solution

Fig. 4-1-2-1: Calorimetric measurements of unextruded DMPC at concentration of 0.1 wt.%

The phase transition of the sample of 0.1 wt% DMPC solutions, which was not extruded,

was measured by means of the Nano DSC. The phase transition is reversible and the

transition temperatures Tm and Tc are at 24.3oC and 23.3oC in the heating and cooling

process, respectively, which is connected with the main transition from gel to fluid lamellar

phase or fluid lamellar back to gel phase. In Fig. 4-1-2-1, the enthalpy △H of the main

phase transition is 23.4 and 28.4 kJmol-1 in both processes. Other additional unappearent

peaks appear around 14oC in the heating process and 9.4oC in the cooling process. It is

called the pretransition effect and the enthalpy of the peak is 2.84 and 2.24 kJmol-1. For

other kinds of phospholipids this effect has been found by DSC method [89]. The

phenomenon could be explained as Trans-Gauche Isomerization (see Ch.1-6). Each kind

of phospholipid has a different transition temperature Tm, such as DMPC at approximately

24.3 oC, that is determined by our Nano DSC (see Fig. 4-1-2-1) and DPPC is approx.

42oC and its pretransition temperature is around 35 oC [90].

010 20 30 40 50 60

-20

-15

-10

-5

T/ oC

100 nmextruded 0.1% DMPC aqueous solution

Scan rate at 0.2oC/min.

Heating process

cooling process

J/s

Fig. 4-1-2-2: Calorimetric measurements of extruded (100 nm) DMPC at concentration of 0.1

wt.%

The 0.1 wt. % DMPC solution after extrusion does not influence the peak values Tm and Tc

much. Both are at 23.9 and 23.2 oC, respectively. The pretransition peaks disappeared.

The main transition gets broader when the vesicle radius of DMPC decreases. The

enthalpies are 16.4 and 14.3 kJmol-1 in the heating and cooling processes. The density of

the DMPC solution decreases and a two-step process is clearly observed by the Nano

DSC, especially for the vesicles smaller than 200 nm [91]. Other phospholipids, such as

DPPC vesicles, in any aggregate dimension do not appear to have similar effects. DSC

measurements show evidence to corroborate density results, showing a splitting of the

main peak that becomes more evident as the chain length decreases and as the curvature

of the aggregate increases [91].

4-1-3 Membrane thickness of unilamellar vesicles [51, 92, 93]

The experimetal SANS data of DMPC is shown in Fig. 4-1-3-1. In order to determine the

membrane thickness of DMPC, the model of Kratky-Porod is selected. Making the polts of

ln((I(q)-Iinf(q))*q2) vs q2 should give the linear portion of gradient. The equation is given by

m

(4-1-3-1)

1E-3 0,01 0,1 1 10

0,1

100

q2/ nm-2

I(q)

q/ nm-1

Fig. 4-1-3-1: Experimental SANS date for 0.1 % DMPC in D2O (100 nm extruded)

Iinf(q) is the intensity at the background and Iinf(q) is read at the red circle position.

0,1 0,2 0,3 0,4 0,5

-20,5

-20,0

-19,5

-19,0

-18,5

ln(I(q)-Iinf(q)*q2)

q2/ nm-2

Fig. 4-1-3-2: Kratky–Porod plot of experimental SANS data

The membrane thickness of DMPC is determined by plot of Kratky – Porod. It is 3.32 nm.

Generally the thickness of phospholipids is around 3 to 5 nm. The thickness of lipid bilayer

is dependent on chainlehgth of lipids [94]. The result in this experiment corresponds with

the publication, although the date presents not an optimal linear function against q2

between 0.001 nm2 to 0.1 nm2.

m = -0.92 nm2

d = 3.32 nm

for 0.1 % DMPC solution

4-1-4 Stability of the unilamellar vesicles

DLS measurements

010 20 30 40 50 60 70 80 90 100110 120

100

150

200

250

300

Time/day

Rh/nm

The Rh of 0.1 % DMPC solution

mixed with

no copolymer

0.05 % 10R5

0.05 % L35

0.05 % Rewopal 6000

0.05 % Kollicoat IR

Fig. 4-1-4-1: Rh of the mixtures in 0.1 % DMPC solution were measured as a function of time

In our experiments we employed the copolymers 10R5, L35, Rewopal 6000 and Kollicoat

IR in a 0.1% DMPC solution at a concentration of 0.05 wt%. After preparation they were

extruded with a polycarbonate filter of diameter 100 nm for 10 times at room temperature.

This large number of extrusions is necessary in order to form long-time stable unilamellar

vesicles. Reducing the number of extrusions shortens the stability time of the unilamellar

vesicles in the solution. Fig. 4-1-4-2 shows Rh of 0.1% DMPC for a different number of

extrusion times as a function of time. The 5 times extrusion which presents a much shorter

stabilty is observed compared to the case extruding 10 times. One observes here that the

slightly turbid solutions without sediment become much more turbid and sediments occur

in solution. It can be explained that unilamellar vesicles, due to the presence of bilayer

material not yet in the form of unilamellar vesicles, are transformed to a state of

multilamellar vesicles or become condensed together.

The results of the hydrodynamic radius Rh of without and with addition of copolymers at

0.05 wt.% into 0.1 wt.% DMPC solution, respectively, are presented in Fig. 4-1-4-1. The

samples were measured day by day after extrusion until the results were not appropriate

because of time-dependent fusion processes. The sample that contains only DMPC keeps

the vesicle size for the longest time. The presence of the different copolymers reduces the

time of stability of the unilamellar vesicles in the solution. Four copolymer mixtures are

100

together with the same characteristics: that they contain ethylene oxide blocks and

connect with other hydrophobic molecules. The individual unilamellar vesicle distributes

homogenously in the solution. It is not easy to approach each other because of hydration

repulsion. When vesicles are closed to each other, a strong repulsion occurs, which can

be measured by means of surface force apparatus (S.F.A) [31, 32]. It can be explained

that unilamellar vesicles after the extrusion method can hold the controlled size in the

solution for a period of time. The times of extrusion and size of controlled particles can

influence the time length of stabilizing unilamellar vesicles.

010 20 30 40 50 60

100

150

200

250

Rh/nm

Time/day

Number of extrusions

5 Times

10 Times

0,1% DMPC extruded with 100 nm polycarbonate filter

Fig. 4-1-4-2: 5 and 10 extrusion times measured by DLS as a function of time for 0.1 %

DMPC solution

The presence of Rewopal 6000 and 10R5 leads to rather short stability times. Both are

telechelic polymers with two hydrophobic end groups on a water-soluble polymer, which

enables them to bridge bilayers. The Rewopal 6000 contains 150 central EO units and

stearyl groups on both ends. Due to its structure, it has the capacity EO to connect two

individual unilamellar vesicles and thereby induce their fusion or formation of multi-

lamellar structures. A similar argument holds for 10R5, with the difference that it contains

only 23 EO units. For Kollicoat IR, the longest time of stability of the unilamellar vesicles is

observed. It contains no hydrophobic units and thereby lacks the ability to bridge vesicle

bilayers. After extrusion, Kollicoat IR could exist in water or attached to the unilamellar

DMPC vesicles. The pure DMPC solution without copolymer additions is the most stable

one in solution.

101

0.1 % DHPC and DMPC solution

In order to produce bicelles vesicles in a solution mixing the variation of DHPC lipids with

DMPC and keeping the concentration is always at 0.1 wt.% in total. Due to the differing

lengths of hydrophilic tails from both, they are highly probable to form the long cylindrical

bilayer vesicles in aqueous solutions, for which the scheme is presented in Fig. 4-1-4-4.

Investigating the stability of bicelles vesicles are with time analysed by the DSL instrument.

-5 0 5 10 15 20 25 30

100

200

300

Rh/ nm

Time/day

the ratio of DMPC and DHPC

MH51

MH31

MH32

MH11

The extruded 0,1 % DMPC and DHPC solution

Fig. 4-1-4-3: Different ratio of 0.1 % DMPC and DHPC solutions (MH51 is the mass ratio of

DMPC and DHPC 5:1, MH31 is 3:1, MH32 is 3:2 and MH11 is 1:1)

Fig. 4-1-4-3 summarizes the Rh and stability investigation of the DMPC and DHPC

solution. The samples are at different mixing of mass ratios but a total concentration are

controlled at 0.1 wt. %. They are all one phase and homogenous after extrusion.

Compared with the pure 0.1% DMPC solution, they result in a short stable time after

extrusion with 100 nm. Different mass ratios of DMPC and DHPC take different lengths of

stable time. The sample MH32 keeps the shortest time of the others. After just the

beginning of the fresh extrusion time, the Rh of MH 32 is around 100 nm. Three days later

the Rh increased to 1000 nm, it is not presented in this curve. Keeping the longest stable

time is the sample of MH11. It keeps over 20 days at the constant Rh, around 90 nm. The

Rh of MH 51 keeps increasing ten days after extrusion. The MH31 shows the unstable Rh

during the ten days. Other publications show that the Rh is around 25 nm to 40 nm for

0.1% lipid concentration, but it contains mostly salts or acids in the solution [95-97].

102

Fig.: 4-1-4-4: Two-dimensional projection of bicelle vesicle and chemical structures of DMPC

and DHPC [98]

103

4-1-5 Permeability [37]

A way to determine the permeability of unilamellar vesicles is to measure the transport of

probe molecules/ions through the bilayer and detect them by means of UV-VIS

spectroscopy and employing a Stopped Flow instrument for high time-resolution. In the

case of our vesicles, this was done by means of using a coloured iron complex and mixing

it with F- ions.

UV-VIS

200 300 400 500 600 700 800

0,0

0,2

0,4

0,6

0,8

1,0

Abs.

with 5 mm quartz cuvette

/ nm

water

DMPC_Fe(SCN)3

DMPC_Fe(SCN)3_NaF

Fig. 4-1-5-1: UV-VIS absorbance spectra at 25oC with thickness of cuvette at 5 mm

The 0.2 wt. % DMPC with iron (III) thiocyanate complex inside presents red colour in the

solution. A strong binding of the iron (III) thiocyanate complex to DMPC phospholipids can

be observed by UV-VIS spectroscopy. The spectra of 0.2% DMPC and 2 mM Fe(SCN)3,

including 200 mM NaNO3 in the solution, have a maximum absorbance at a wave length

of 450 nm. After mixing with 200 mM NaF solution at a volumen ratio of 1 to 1 the red

colour disappears because Fe(SCN)3 with F- solution turns to (FeF6)3- and SCN- irons in

the solution. This results in the spectra for sample DMPC_Fe(SCN)3_NaF not expecting a

peak at the 450 nm position. After mixing with the NaF solution shows a white, the sample

is a turbid, non-homogenous solution.

104

Stopped Flow

It is assumed that the reaction between the FeSCN2+ complex and F- ions outside of the

vesicles is faster than the deadtime of the Stopped Flow experiments. For the reaction

between FeSCN2+ inside the vesicles and F- outside the vesicles, one type of ion must

permeate through the vesicle membrane.

010 20 30 40

0,00

0,02

0,04

0,06

0,08

0,10

0,12

0,14

0,16

0,18

Time/sec.

Abs.

Acquisition start: 10 ms before stop

a. water

b. 2 mMFe(SCN)3

c. 0.2 MPC (100nm) and 2 mM Fe(SCN)3 + 200 mM NaF

d. 2 mM Fe(SCN)3 + 200 mM NaF

e. 0.2 % DMPC(100nm)

Fig. 4-1-5-2: Absorbance of stopped-flow signals at 25oC and at a wave length of 450 nm.

(deadtime: 10 ms)

The solution in Stopped Flow measurements contains 0.2 wt. % DMPC unilamellar

vesicles, which has been extruded with an 100 nm filter, 2 mM FeCl3, 6 mM NH4SCN, 200

mM NaNO3 and was mixed with a solution containing NaF. The amount of NaNO3 was

equal to that of the NaF solution in order to prevent osmotic pressure differences. Fig. 4-1-

5-2 shows water used as the baseline; curve b is the iron (III) thiocyanate complex

solution without phospholipid vesicles and has a high absorbance at 450 nm. Curve d is

the iron (III) thiocyanate complex solution mixed with 200 mM of NaF solution in the

volumen ratio of 1 to 1 that contains no phospholipids vesicles, either, which show a low

absorbance. Curve e is the DMPC solution at 0.2 wt.% and this sample has been already

extruded ten times with a 100 nm polycarbonate filter. Curve c is the 0.2% DMPC vesicles

containing 2 mM Fe(SCN)3 and 200 mM NaNO3 after mixing with 200 mM NaF and

showing a decreasing exponential curve as a function of time. The DMPC solution with

ions is more turbid than the pure DMPC solution, because the absorbance intensity is

higher than pure DMPC (curve e). From the relaxing curve it can be concluded that the

movements of ions for FeSCN2+ diffuse outside of membrane and/or F- diffuse inside of

membrane. The vesicles are detected by passing through the DMPC bilayer here. The

signal for curve c can be analysed by a stretched exponential fit and the equation is given

105

 

 





/exp tA 

, (4-1-4-1)

where

A

is the absorbance change of the signal,



is the relaxation time, and



the stretching factor, typically between 0.4 and 0.7. In this dissertation, the sample for

Stopped Flow was measured only at fixed concentration of 0.2% DMPC, ions and

complex for the 200 mM NaF and 2 mM FeSCN2+ solution to observe the kinetic

movements of irons penetrating into the vesicle of DMPC. If the complex and FeSCN2+ is

increased as a function of concentration for fixed phospholipids, the relaxation time



decreased. However, increasing the concentration of NaF solution did not modify the



not much [37].

0,01 0,1 1 10 100

0,02

0,04

0,06

0,08

0,10

0,12

Abs.

Time/sec.

10R5 in 0.2 % DMPC, Fe(SCN)3 solution + NaF

10R5/ wt. %

0 %

0.02 %

0.04 %

0.2 %

0.4 %

Fig. 4-1-5-3: Abs. of Stopped Flow in the presence of 10R5 at a wavelength of 450 nm

Fig. 4-1-5-3 shows the results of 0.2% DMPC, 2 mM Fe(SCN)3 with 200 mM NaF after

mixing at a volumen ratio of 1 to 1. In the presence of 10R5, the kinetic rate of the

FeSCN2+ and F- ion reaction increases. At the concentration of 0.02% 10R5 the relaxtion

time is reduced to 5.86 seconds and for 0.04% 10R5 it decreases sharply to 0.36 seconds,

(summarized in Tab. 4-1-5-1). The sample of 0.4% 10R5 appears increasing baseline after

absorbance intensity decreases to 0.055. It is caused by the redundant sediments of

molecules from DMPC, Fe(SCN)3, NaF and NaNO3.

106

Tab. 4-1-5-1: Relaxtion time τ of 0.2 % DMPC solution in the presence of 10R5 and L35

10R5/wt. %

τ/ sec

L35/wt. %

τ/ sec

6.62

0.02

5.86

0.02

8.36

0.04

0.36

0.04

32.85

0.2

0.32

0.1

48.60

0.4

0.2

Tab. 4-1-5-1 summarizes the relaxtion time



of the 0.2% DMPC vesicle solution in the

presence of 10R5 and L35, respectively.

0,01 0,1 1 10 100

0,04

0,08

0,12

0,16

L35 in 0.2 % DMPC, Fe(SCN)3 solution + NaF

Time/ sec

Abs.

L35/ wt. %

0 %

0.02 %

0.04 %

0.1 %

0.2 %

Fig. 4-1-5-4: Abs. of Stopped Flow in the presence of L35 at a wave length of 450 nm

Fig. 4-1-5-4 shows the absorbance of Stopped Flow at 450 nm for the sample of 0.2%

DMPC small vesicles and ions solution in the presence of L35. The relaxtion time



increased in the presence of L35. The intensity of absorbance decreased because the F-

ions react with Fe(SCN)2+. When L35 is increased to 0.2 wt.% in the solution, no optimal

curve appears as a function of time. The baseline increases as a function of time after

mixing with a volumen of NaF and it is because of sediments caused by copolymer L35.

107

Equations (1-7-12) and (1-7-13) give a relation between the relaxation time of the Stopped

Flow signals and the calculated permeability coefficients. In this situation the relaxation

time should be independent of the concentration of F- and FeSCN2+ under the

experimental conditions.

In this experiment, the relaxation time of the DMPC solution is analysed by the Stopped

Flow. The first-order rate constant of kexp can be calculated with eq. 1-7-15 and the value

results in 0.151 s-1. The permeability coefficient P is calculated by eq. 1-7-14 and the

value is 3.52 x 10-7 cm/s. For the vesicles of egg phosphatidyl choline the permeability P

is the range of 2 x 10-4 cm/s [37]. The vesicles of DMPC results in that the permeability is

slower than the vesicles of egg phosphatidyl choline. The presence of 10R5 and L35 in

0.2% DMPC, respectively, is summarized in Tab. 4-1-5-2. The radius of DMPC vesicles,

including additives, takes 70 nm.

Tab. 4-1-5-2: Results of Kexp and P of 0.2 % DMPC in the presence of 10R5 and L35

Additives and 0.2 % DMPC unilammelar vesicle solution

10R5

L35

Con/wt.%

Kexp/s-1

P/cm．s-1

Con./ wt. %

Kexp/s-1

P/cm．s-1

0.151

3.52x10-7

0.151

3.52x10-7

0.02

0.171

3.99x10-7

0.02

0.120

2.80x10-7

0.04

2.78

6.49x10-6

0.04

0.030

7.0x10-8

0.2

3.13

7.30x10-6

0.1

0.021

4.9x10-8

The presence of 10R5 decreases the relaxtion times of DMPC vesicles solutions and the

presence of L35 increases. Rate constant of Kexp is inversely proportional to relaxtion time

τ. By adding the 10R5 into DMPC vesicles solution, it lets the Kexp increase but the Kexp

of DMPC is decreased by adding L35. The permeability of DMPC solution is increased in

the presence of 10R5, but is decreased in the presence of L35.

108

4-1-6 Conductivity

0,00 0,02 0,04 0,06 0,08 0,10

400

410

420

430

440 0,00 0,02 0,04 0,06 0,08 0,10

400

410

420

430

/ scm-1

L35, 10R5/ wt.%

10R5 at

25 oC

35 oC

L35 at

25 oC

35 oC

Copolymer and 0.2% DMPC solution (2 mM KCl)

Fig. 4-1-6-1: Conductivity of L35 and 10R5 in 0.2 % DMPC (2 mM) respectively

The respective results of conductivity of 0.2% DMPC solution in the presence of L35 and

10R5 are shown in Fig. 4-1-6-1. Both have been already extruded 10 times by a 100 nm

filter before measuring. The samples contain 2 mM KCl to achieve a reasonable value of

conductivity, because the conductivity of DMCP is extremely low. The presence of L35

and 10R5 only influence the conductivity of 0.2% DMPC solution a little. They are

prepared with the concentration of 0.05% and 0.1% in the 0.2% DMPC solution. At 25oC

the maximal conductivity for L35 is at 0.1% but for 10R5 is at 0.05%. When the

concentration of 10R5 increases to 0.1% in 0.2% DMPC solution, the conductivity reduced.

If the samples are measured at 35oC, the pure 0.2% DMPC solution results in a higher

conductivity value than at 25oC. The presence of L35 leads to no influence on the

conductivity when the temperature increases to 35oC. However for 10R5 the highest

conductivity is at 0.05%. When the temperature is increased to 35 oC, the conductivity is

increased. This sample was measured at two different temperatures.

109

4-2 Diesterquat CR3099 solution

The surfactant CR3099 is of the diesterquat type, and based on oleic acid. Due to some

advantages like fast water film displacement, its ability to impart shine and optimal

hydrophobic properties it is widely used in commercial applications [99-102]. Typically it

forms vesicles in aqueous solution [103]. The CR3099 surfactant is compatible with non

compatible with non-ionic and amphoteric surfactants and is no problem in a pH range

between acidic and slightly alkaline [104]. However it is incompatible with anionic

surfactants due to the formation of insoluble surfactant complexes.

4-2-1 Phases Behaviour

Fig. 4-2-1-1: Pictures of 0.5% CR3099 solution before extrusion (left) and after extrusion with

100 nm (middle and right)

CR3099 dissolved in water at a concentration of 0.5% is a cloudy and homogeneous

solution (Fig. 4-2-1-1). After extrusion with a 100 nm filter, the turbidity of the sample

becomes weaker as the size of particles is reduced in the solution. The extruded sample

is very stable and only observed under macroscopic conditions. Over six months, the

phase behaviour of the extruded sample (see Fig. 4-2-1-1) remains unchanged, which is

clearly different to the ageing behaviour typically seen for phospholipids.

110

4-2-2 Stabilityof small vesicles for the CR3099 solution

DLS Measurements

040 80 120 160 200 240 280

100

120

140

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

Time/day

Rh/nm PD.I

0,5% Diesterquat extruded via 100 nm polycarbonate filter

PD.I

Fig. 4-2-2-1: Results of Rh and PD.I with the function of time

Fig. 4-2-2-1 gives the hydrodynamic radius as a function of time for a 0.5% CR3099

solution, which has been extruded with 100 nm poly carbonate filters, and investigated

over the course of six months. Before extrusion, the Rh of 0.5 % CR3099 solution is

202.9 nm and the PD.I is 0.31. The radius can be induced depending on the concentration.

After extrusion with a 100 nm filter, the Rh decreases to around 100 nm and the values of

the PD.I are around 0.33. They remain constant during this period of time. The PD.I of the

0.5% CR3099 solution is not influenced strongly by the method of extrusion. The

molecules of diesterquat can be biogradegated by bacteria, especially with a CO2-monitor

[105]. However, all CR3099 samples, even without any protection agents, like NaN3, show

no signs of biogradegation.

111

0,0 0,5 1,0 1,5 2,0

120

160

200

240

280

320

0,30

0,32

0,34

0,36

0,38

0,40

0,42

0,44

Rh/ nm

CR3099/ wt.%

Rh/ nm

PD.I

CR3099 aqueous solution

PD.I

Fig. 4-2-2-2: DLS measurements of CR3099 solution as function of concentration

Diesterquat CR3099 forms vesicles in solution. The Rh of CR3099 is dependent on the

concentration. The sample of 2.0 % results the largest Rh of CR 3099 solution. Fig. 4-2-2-

2 presents the Rh and PD.I of CR3099 as function of centration. They are measured

without extrusion. The sample of 0.5 % results the lowest PD.I values of CR3099 solution.

4-2-3 Membrane thickness of the unilamellar vesicles

SANS measurements

The samples were dissolved in D2O directly and without any extrusion. They were

measured by Dr. Sylvain Prévost at ILL in Grenoble, France.

0,01 0,1

0,1

100 CR3099 / wt.%

0.25 %

0.50 %

1.0 %

2.0 %

q/ A-1

I(q)/cm-1

CR3099 (Diesterquat) solution in D2O

Fig. 4-2-3-1: Experimental SANS data for CR3099 in D2O

112

Fig. 4-2-3-1 presents the SANS date of the CR3099 solution from 0.25 % to 2.0 %.

Making a plot of ln(I(q)-Iinf(q)q2) vs q2 gives a straight line portion of gradient -d2/12 where

d is the second moment of the vesicle lamella thickness [92, 93]. Iinf(q) is the intensity at

the background and Iinf(q) is read at red circle position. The curve is shown as follows:

0,01 0,02 0,03 0,04 0,05

-31

-30

-29

-28

-27

-26

-25

q2/ nm-2

ln(I(q)-Iinf(q)*q2)

CR3099/ wt.%

0.25 %

0.5 %

1.0 %

2.0 %

Fig. 4-2-3-1: Kratky-Porod plots of the SANS data obtained from CR3099 in D2O

Tab. 4-2-3-1 summarizes the slope of CR3099 and the thickness of the vesicles. The

vesicle thickeness of CR3099 is slightly dependent on the concentration.

Tab. 4-2-3-1: slop and thickness of CR3099

CR3900/ wt.%

Slop/ nm2

d/ nm

0.25

-92.29

33.28

0.5

-110.94

36.49

1.0

-115.24

37.19

2.0

-112.10

36.68

113

4-2-4 Additive and CR3099 solution

In the following, our focus was then on the effect of adding amphiphilic polymers to these

vesicle solutions in order to see how their presence affects the structure and stability of

the CR3099 vesicles.

10R5 and 0.5 % CR3099 solution

We then studied the effect of the copolymer 10R5 on the vesicle structure of CR3099. To

that end, 10R5 was added in fixed amounts directly to a 0.5% CR3099 solution. For the

preparation, one day of homogenisation was done and homogenous solutions were

always obtained.

DLS measurements

Investigating the effect on the vesicles of CR3099 is analysed by the DLS in the presence

of 10R5. The samples were traced for at least one month.

050 100 150 200 250

100

Time/day

Rh/nm

0,5% Esterquat and 10R5 extruded via 100 nm polycarbonate filter

10R5 /wt.%

0.01%

0.02%

0.05%

0.1%

0.2%

0.3%

0.4%

0.5%

0.8%

1.0%

Fig. 4-2-4-1: Rh of increasing 10R5 in a fixed 0.5 % CR3099 solution respectively as a

function of time

The Rh of a 0.5 % CR3099 solution containing the various amounts of 10R5 remains

stable for over a half a year after extrusion. The additional mixture of a telechelic polymer,

like 10R5, has an influence on the hydrodynamic radius of a CR3099 solution after

extrusion. The Rh of 0.5% CR3099 decreases upon the addition of 10R5 (Fig. 4-2-4-1).

114

The reduced Rh is proportional to the amounts of 10R5 in a fixed CR3099 solution. Only

for the smallest amount of 10R5 (0.01%) does the Rh for the 0.5% CR3099 solution

remain unchanged. Upon increasing the concentration to above 0.02%, Rh becomes

reduced. For these 10R5-containing samples, a slow decrease of particle size over the

course of weeks is observed. For the higher concentrations of 10R5 (0.3%, 0.5%, 0.8%,

1.0%) they were prepared later and therefore measured only for a shorter period of time.

0,01 0,05 0,2 0,4 0,8

100

0,10

0,15

0,20

0,25

0,30

0,35

PD.I

10R5 and 0,5% Diesterquat extruded via 100 nm filter

10R5/ wt.%

Rh/nm

PD.I

Fig. 4-2-4-2: Results of Rh and PD.I present as a function of 10R5 in a 0.5 % CR3099 solution.

Both values are calculated based on the average of their own total measuring day.

Fig. 4-2-4-2 summarizes the results of the hydrodynamic radius Rh and polydispersity

index PD.I as a function of 10R5 in 0.5% CR3099 solutions. By adding 10R5 into the 0.5%

CR3099 solution, the PD.I and Rh are influenced. Both values are decreased

proportionally as a function of concentration. The decreasing values of Rh and PD.I do not

appear as an optimal linear function. The Rh of the sample 0.3% is higher than 0.2% and

the PD.I of the sample 0.02% is lower than 0.05%.

115

Results of Viscosity

Measuring the viscosity of a 0.5% CR3099 solution was done by means of an ubbelohde

viscosimeter.

0 0,01 0,02 0,05 0,1 0,2 0,4

1,00

1,05

1,10

1,15

1,20

1,25 10R5 (100 nm)

L35 (100 nm)

10R5 no extrusion

/mm2s-1

10R5 or L35/ wt.%

10R5 and L35 in 0.5% CR3099 in H2O

Fig. 4-2-4-3: Results of viscosity for 10R5 (extruded and unextruded) and L35 (extruded) in

0.5% CR3099 solutions, respectively, as a function of concentration

Fig. 4-2-4-3 shows the respective viscosity results of 10R5 and L35 in a 0.5% CR3099

solution as a function of concentration. Basically constant values are seen. Apparently, the

10R5, with its hydrophobic end groups, is not able to lead to a cross-linking of the vesicles

that should lead to an increased viscosity. The samples prepared without extrusion at the

concentrations of 0.1% and 0.2% show somewhat higher viscosity values. This can be

correlated to the larger particle size and the corresponding larger effective volume fraction.

116

Kollicoat IR and 0.5 % CR3099 solution

In the following we then studied the effect of the polymer Kollicoat IR on the vesicle

structure of CR3099. To that end, Kollicoat IR was added directly, in fixed amounts, to a

0.5% CR3099 solution. For the preparation, one day of homogenisation was done and

homogenous solutions were always obtained.

050 100 150 200 250

100

Rh/nm

Time/day

Kollicoat IR /wt.%

0.01%

0.02%

0.05%

0.1%

0.2%

0.3%

0.4%

0.5%

0.8%

1.0%

Kollicoat IR and 0,5% Diesterqaut extruded via 100 nm filter

Fig. 4-2-4-4: Rh of increasing Kollicoat IR in fixed 0.5% CR3099 solutions, respectively, as a

function of time

Fig. 4-2-4-4 presents the results for the hydrodynamic radius of 0.5% CR3099 solutions

with increasing concentrations of Kollicoat IR, varying from 0% to 1.0%, that were

regularly measured by means of the DLS over the course of six months. The addition of

Kollicoat IR leads to reduced Rh values where the reduction is proportional to the

concentration of Kollicoat IR. A substantial decrease of Rh was already observed for the

lowest concentration of Kollicoat IR of 0.01%. With time, the particle size tends to

somewhat decrease.

117

0,01 0,05 0,2 0,4 0,8

100

0,10

0,15

0,20

0,25

0,30

0,35

Rh/nm

Kollicoat IR/ wt.%

Kollicoat IR and 0,5% Diesterquat extruded via 100 nm filter

PD.I

Fig. 4-2-4-5 : Results of Rh and PD.I present as a function of Kollicoat IR in 0.5 % CR3099

solutions. Both values are calculated based on the average of their own total measuring day.

Fig. 4-2-4-5 shows the results of Rh and PD.I values as functions of Kollicoat IR in a 0.5%

CR3099 solution. The presence of Kollicoat IR leads to decreasing Rh and PD.I values. At

low concentrations of Kollicoat IR, like the samples of 0.01% and 0.02%, it presents

unexpected results. The Rh and PD.I of sample 0.02% are higher than sample 0.01%.

This could be due to the uncertainty of small amounts and the experimental inaccuracy.

118

5. Addition of polymers to gel phases of multilamellar vesicles (MLV)

(TDMAO, TTABr and 1-Hexanol)

In this part we investigated the effect of the addition of polymers on the properties of a gel

phase densely packed with multilamellar vesicles (MLV). This viscoelastic phase contains

densely packed MLV, composed of alkyldimethylaminoxides (CxDMAO), n-alcohols (C6-C9)

and the ionic surfactant tetradecyltrimethylammonium bromide (C14-TMABr) or sodium

dodecyl sulphate (SDS) [106]. For our experiments, we selected TDMAO, TTABr and 1-

Hexanol as amphiphilic components in aqueous solutions.

5-1 Phases behaviour

Fig. 5-1-1 : Schematic quaternary phases diagram of TDMAO, TTABr, 1-Hexanol and water at

25oC and a total surfactant concentration of 100 mM and for varying concentrations of 1-

Hexanol [106]

Fig. 5-1-1 summarizes the phase behaviour of zwitterionic tetradecyldimethylamineoxide

(TDMAO), cationic tetradecyltrimethylammonium bromide (TTABr), 1-Hexanol and water

at 25°C. The phase behaviour depends strongly on the ratios of TDMAO, TTABr and 1-

Hexanol. In this system, vesicles are formed easily in the presence of the cationic

surfactant TTABr in the ternary system of TDMAO/1-Hexanol/H2O [57, 107-109]. The

Phase L1 is the isotropic micellar solution, Lα1 the vesicle phase, and Lαh the classical

☆

119

lamellar phase of planar bilayers. In our experiment, the concentrations of TDMAO, TTABr

and 1-Hexanol are 90 mM, 10 mM and 220 mM, respectively. They fall into the phase

diagram regime indicated by the single star. The other solution contains the same ratio of

TDMAO and TTABr, but the 1-Hexanol increases to 350 mM. It is close to Lα phase but

still at the range of L1 + Lα phase.

90 mM TDMAO, 10 mM TTABr and 220 mM 1-Hexanol solution with 220 mM and

350 mM respectively

Fig. 5-1-2 : Gel solution of 90 mM TDMAO, 10 mM TTABr with 220 mM and 350 mM 1-Hexanol

(right and left)

Fig. 5-1-2 shows the phase behaviour of a gel solution of 90 mM TDMAO and 10 mM

TTABr with different concentrations of 220 mM and 350 mM 1-Hexanol respectively. The

sample of 90 mM TDMAO, 10 mM TTABr and 220 mM 1-Hexanol is in the gel phase,

which is homogeneous, transparent and highly viscous. When the concentration of 1-

Hexanol is increased to 350 mM, the sample is more turbid and the viscosity is lower.

120

10R5 and 90 mM TDMAO, 10 mM TTABr and 220 mM 1-Hexanol solution

Fig. 5-1-3 : (From left to right) 0 %, 1.0 % and 2.0 % of 10R5 in gel solution of 90 mM TDMAO,

10 mM TTABr and 220 mM 1-Hexanol

The addition of 10R5 does not lead to larger differences in the gel phase of 90 mM

TDMAO, 10 mM TTABr and 220 mM 1-Hexanol. The amounts of added 10R5 are 1.0%

and 2.0%, respectively, and the solutions remain homogeneous and clear.

10R5 and 90 mM TDMAO, 10 mM TTABr and 350 mM 1-Hexanol solution

Fig. 5-1-4 : (From left to right) 0 %, 1.0 % and 2.0 % of 10R5in gel solution of 90 mM TDMAO,

10 mM TTABr and 350 mM 1-Hexanol

121

The mixture of 90 mM TDMAO, 10 mM TTABr and 350 mM 1-Hexanol presents turbid but

homogeneous gel phases. The presence of 10R5 clarifies the turbid gel phase. If the

amounts of 10R5 increases to 2%, the sample at the right side, becomes more

transparent compared to the sample of 0% at left side.

Rewopal 6000 and 180 mM TDMAO, 20 mM TTABr and 400 mM 1-Hexanol

solution

Fig. 5-1-5: Samples of Rewopal 6000 at 0, 0.2, 0.6 and 1.0% (from left to right) in the gel

solution of 180 mM TDMAO, 20 mM TTABr and 400 mM 1-Hexanol

Fig. 5-1-5 shows the gel solutions of a mixture of 180 mM TDMAO, 20 mM TTABr and 400

mM 1-Hexanol. The concentrations of TDMAO and TTABr were doubled and 1-Hexanol

increased to 400 mM. It remains homogenous, transparent and turns into a strongly

viscous, gel-like solution. The appearance of the gel solution becomes less turbid in the

presence of Rewopal 6000. However the viscosity is hard to tell if it is affected by

Rewopal 6000.

122

5-2 Properties of gel phases

Amplitude sweep

1E-3 0,01 0,1 1 10

100

nonlinear viscoselastic

*/ Pas

180 mMTDMAO, 20 mM TTABr and 400 mM 1-Hexanol

G',G''/Pa

Strain

Elastic Modulus Pa , G'

Viscous Modulus Pa , G''

Complex Viscosity Pas

Linear viscoselastic

Fig. 5-2-1: Amplitude rheogram of a solution 180 mM TDMAO, 20 mM TTABr and 400 mM 1-

Hexanol

The modulus for the sample of 180 mM TDMAO, 20 mM TTABr and 400 mM 1-Hexanol

results in two parts of viscoselastic characteristics as functions of strain. In the first part,

the elastic modulus and the complex viscosity are independent of the strain. They obey

the linear viscoselastic rule when the strain increases to 0.1 Pa. If the strain force

continues to increase to 10 Pa, the appearance of nonlinear viscoselastic phases are

observed. In the second part, the elastic modulus and complex viscosity decrease after

the strain forces grow from 0.1 Pa to 10 Pa. The viscous modulus G’’ of the sample does

not behave totally independently of the strain force in the first part. It results in the same

phenomenon as other parameters in the second part of strain range. The decreasing

plateau begins around 0.5 Pa, which is higher than the elastic modulus and complex

viscosity.

123

Frequency sweep

0.01 0.1 1 10

100

1000

10000

G',G''/ Pa

f/ Hz

Elastic Modulus Pa , G'

Viscous Modulus Pa , G''

Complex Viscosity Pas

*/ Pas

180 mMTDMAO, 20 mM TTABr and 400 mM 1-Hexanol

Strain at 0.0036

Fig. 5-2-2 : Oscillatory rheogram of a solution 180 mM TDMAO, 20 mM TTABr and 400 mM 1-

Hexanol

The frequency sweep curve gives us good rheological information on the materials how

they behave during storage and application. It is a useful test to determine the viscoelastic

properties of samples as a function of timescale. Several parameters would be obtained,

such as Storage (Elastic) Modulus G', the Viscous (Loss) Modulus G", and the Complex

Viscosity η*. The figure is the typical for a well-structured gel system. The elastic modulus

G' is greater than the viscous modulus G" and both are almost independent of frequency.

In this case, it is impossible for sedimentation to occur. There are other typical cases like

non-associated particulate dispersion and weakly-structured systems. The frequency of a

sweep curve of non-associated particulate dispersion appears in the viscous modulus,

which is dominant over the elastic modulus. Both of these are highly dependent on

frequency. Besides, the complex viscosity is almost independent of frequency. The other

system results in that the viscous modulus is greater than the elastic modulus. However,

the difference between these is less great than in the non-associated system. The

complex viscosity is also now dependent on the frequency.

124

0.01 0.1 1 10

100

1000 0.01 0.1 1 10

0.1 1 10

100

1000

G'/ Pa

f / H z

D i f f e r e n t r a t i o o f T D M A O , T T A B r

a n d 1 - H e x a n o l s o l u t i o n

G''/ Pa

*/ Pas

S a m p l e

Fig. 5-2-3: Oscillatory result of different ratios of TDMAO, TTABr and 1-Hexanol in solutions

In this part, three solutions composed of various concentrations of TDAMO, TTABr and 1-

Hexanol, as shown in Tab. 5-2-1, were measured by Rheology.

Tab. 5-2-1: Ratio of TDMAO, TTABr and 1-Hexanol

Sample

TDMAO/ mM

TTABr/ mM

1-Hexanol/ mM

220

350

180

400

Three parameters – G’, G’’ and η* – are measured as a function of frequency from 0.01 Hz

to 10 Hz. At the given constant strain sample A and B result in optimal stability and little

dependency on frequency in the elastic modulus. Sample C results in higher elastic

characters than do samples A and B. This is due to the doubling of the concentration

compared to sample A. Sample B leads to an increase of the elastic property when the

frequency increases to 10 Hz. In the viscous modulus, all three samples result in lower

values than in the elastic modulus. Below 5 Hz the viscosity is independent of frequency.

The complex viscosity is linearly dependent on frequency when the frequency is close to

10 Hz.

125

10R5 in a 90 mM TDMAO 10 mM TTABr and 220 mM 1-Hexanol solution

0.01 0.1 1 10

30 0.01 0.1 1 10

0.1

10 0.01 0.1 1 10

0.1

100

G'/ Pa

f/ Hz

10R5/ wt.%

0 %

1 %

2 %

10R5 in 90 mM TDMAO, 10 mM TTABr

and 220 mM 1-Hexanol solution

G'' / Pa

*/ Pas

Fig. 5-2-4: Oscillatory result of 10R5 in a 90 mM TDMAO, 10 mM TTABr and 220 mM 1-

Hexanol solution

In the elastic modulus, the three samples show little dependency on frequency; in addition,

the presence of 10R5 in 90 mM TDMAO, 10 mM TTABr and 220 mM 1-Hexanol induces

the values of elastic modulus. The sample of 1.0% 10R5 shows the lowest elastic

appearance in comparison to the other two samples; moreover, it decreases dramatically

at high frequencies. The elastic property increases when the concentration of 10R5

increases by 2% in the same parent gel solution. In the viscous modulus, the samples of 0

and 2% 10R5 tend to decrease with respect to frequency. On the other hand, the sample

of 1% keeps constant viscose value independent of frequency. However they decrease

sharply between 7 and 9 Hz. At 10 Hz, the viscous modulus becomes slightly higher than

the original value. The sample of 1% 10R5 contains the lowest elastic properties and

leads to lowest G’’ value at a high frequency range. The values of complex viscosity are

decreased in the presence of 1% 10R5 and increased slightly when the 10R5 increased to

2%.

126

10R5 in a 90 mM TDMAO 10 mM TTABr and 350 mM 1-Hexanol solution

0.1 1 10

100 0.1 1 10

0.1

10 0.1 1 10

100

10R5 in 90 mM TDMAO, 10 mM TTABr

and 350 mM 1-Hexanol solution

G' / Pa

f / Hz

G'' / Pa

*/ Pas

10R5/ wt.%

0 %

1 %

2 %

Fig. 5-2-5: Oscillatory result of 10R5 in a 90 mM TDMAO, 10 mM TTABr and 350 mM 1-

Hexanol solution

With the same concentrations of TDMAO and TTABr, that of 1-Hexanol increases to

350 mM and the phase becomes turbid. The rheological parameters G’ and η* do not

change much; however, when 10R5 is added to this solution, elasticity and complex

viscosity are enhanced, especially at the low frequency range. When the frequency is

close to 10 Hz, the values of 1% and 2% 10R5 are closer to each other. It indicates that

three samples share similar properties of both moduli at high frequencies. In a viscous

modulus, regular and limited variation appears when the samples contain 10R5 in the

solution. This indicates that the presence of 10R5 disturbs the constant stability value of

pure gel turbid solution. The sample of 0% has lower values at high frequency. The lowest

value of G’’ appears when the sample contains 1% 10R5.

127

Rewopal 6000 in a 180 mM TDMAO, 20 mM TTABr and 400 mM 1-Hexanol

solution

0.1 1 10

150

200

250

300

0.01 0.1 1 10

100 0.1 1 10

100

1000

G'/ Pa

G''/ Pa

f / H z

R e w o p a l 6 0 0 0 i n 1 8 0 m M T D M A O ,

2 0 m M T T A B r a n d 4 0 0 m M 1 - H e x a n o l

*/ Pas

Rewopal 6000/ wt.%

0 %

0.2 %

0.6 %

1.0 %

Fig. 5-2-6: Oscillatory result of Rewopal 6000 in a 180 mM TDMAO, 20 mM TTABr and 400

mM 1-Hexanol solution

The gel solution of 180 mM TDMAO, 20 mM TTABr and 400 mM 1-Hexanol results in

higher G’, G’’ and η* values in comparison to the other two gel solutions. The presence of

Rewopal 6000 are influenced the values of G’, G’’ and η*. The results show that they

increase non-linearly with respect to the amounts of Rewopal 6000. In all three

parameters, the sample of 0.2% has greater values than the sample of 0.6%; meanwhile,

the value of both samples falls behind the 1.0% sample. The elastic and viscous moduli

are almost independent of frequency. In every sample, the elastic modulus shows higher

pascal than the viscous modulus; in addition, the complex viscosity decreases with

respect to the frequency after the addition of Rewopal 6000. It indicates that Rewopal

6000 does not influence the good structure of the gel solution; however, it promotes all G’,

G’’ and η*.

128

F108 in a 180 mM TDMAO, 20 mM TTABr and 400 mM 1-Hexanol solution

0.1 1 10

120

160

200 0.1 1 10

16 0.1 1 10

100

1000

G' / Pa

f / H z

F 1 0 8 i n 1 8 0 m M T D M A O , 2 0 m M T T A B r

a n d 4 0 0 m M 1 - H e x a n o l s o l u t i o n

G'' / Pa

*/ Pas

F108/ wt. %

0 %

0.2 %

0.6 %

1.0 %

Fig. 5-2- 7: Oscillatory behaviour of F108 in a 180 mM TDMAO, 20 mM TTABr and 400 mM 1-

Hexanol solution

In this part, the triblock copolymer F108 is selected to mix with the gel solution of 180 mM,

20 mM TTABr and 400 mM 1-Hexanol at weight concentrations from 0 to 1.0 %. The

presence of F108 influences the elastic modulus mostly visibly. The value of G’ increases

substantially upon the addition of F108. However the other parameters, like viscous

modulus and complex viscosity, are not much affected by the presence of the F108. One

explanation for these increased elastic properties could be that a bridging of the MLVs by

the presence of the telechelic polymer occurs here.

Fig. 5-2-8: Schematic MLVs and additives.

Additive

MLVs with additive

129

6. Conclusions and outlooks

The first part puts the solubilisation of differently polar oils in solutions of amphiphilic

triblock copolymer F108 as a function of temperature is studied. In general, in the

presence of F108, the solubility of the selected oils in aqueous solution is enhanced. At

the same time the presence of the oils enhances the propensity of the Pluronics to

micellise. In this process, the originally present unimers get together to form micellar

aggregates. In general, for these copolymers, micellisation is related to the dehydration

process of the PO blocks, which takes place upon increasing the concentration and/or the

temperature. However, the addition of the polar oils also facilitates this dehydration

process and thereby can largely reduce the critical micellisation temperature (cmt), where

this effect depends strongly on the molecular architecture of the oil and in general is

proportional to the amount of it present. Here medium chain alcohols, such as hexanol or

geraniol, are very effective. These changes were followed by a DSC, which can easily

detect the enthalpy connected with the dehydration of PPO. From the peak position one

can define the value of the critical micelle temperature (cmt). At the same time the

homopolymer PPO and the copolymer Kollicoat MAE do not influence the temperature of

the phase transition peaks. In the presence of PPO a shoulder peak combine with thermal

peak is observed and it shifts to lower temperatures with increasing concentrations.

Observing the phase behaviour of PPO in 3.6 mm F108, the turbid solution appears at the

given temperature that the shoulder peak appears. This phenomenon is explained as the

cloud point. There is a very high probability that it is caused by homo compolymer PPO.

The triblock copolymer F108 has its own cloud point as well. It appears when the PO and

EO blocks are dehydrated. The dehydration process of EO blocks needs more energy

than PO blocks, so it takes two steps to reach the cloud point. This thesis presents not

futher evidence that the shouder peak caused by PPO because of cloud point. The

enthalpy ΔH(PO) of F108 in the presence of PPO is much higher than 1-Hexanol. The

enthalpy is enhanced by it, but it has no influence on lowering the cmt. The presence of

Kollicaot MAE decreases the thermal peak of F108 and so does the enthalpy. Limited to

the time, there is more information to find out what their behaviour is like in the thermal

property. The viscosity of Kollicoat MAE increases in the presence of F108. Deprotonating

the samples and controlling the PH value around 6 results in higher values of viscosity.

The Rh of F108 solution, in the presence of polar oil for unimer and micelle phases, was

determined by means of DLS because it were measured as a function of temperature. The

Rh of the unimer phase was found at low tempweratures when F108 was not in the

dehydration process. If the temperature is controlled over its cmt, the determined Rh

belongs to size of micelle phases. However, the dehydration process is still not over, and

130

the temperature keeps on increasing to 35 and 40oC and the Rh of micelle decreases but

not by much. The shape of the micelle has formed, but inside the micelle still contains the

remaining water, which continues to discharge from PO blocks when the temperature is

already increased above the cmt. The presence of polar oil seems not to induce the size

of miclle phases but to let the Rh of micelle form in advance. In other words, it has been

once again confirmed by the DLS the presence of polar oil affects the lowering of the cmt

of the fixed F108 solution.

In the SANS measurements it has been proved that the presence of 1-Hexanol is soluble

certainly in F108 solution. The results of parameters, which are analysed with SASfit

programmes, are not conclusive in interpreting the appearance of the F108 solution in the

presenece of 1-Hexanol. However, the best fit curve is obtained with measurements. The

scattering intensity increases with increasing amounts of 1-Hexanol, especially at the

middle q position. It proves indirectly that the existence of 1-Hexanol dissoved in F108

D2O solution at the certain range of fixed environments.

In the second part, the interaction of phospholipids and diesterquats with amphiphilic

copolymers was investigated with respect to the structure and stability of the unilamellar

vesicles formed in these solutions. By means of increasing the number of times of

extrusion, the stability of the formed unilamellar vesicles was substantially enhanced

beyond a certain number of extrusions. The presence of amphiphilic copolymers, like

10R5, L35, Rewopal 6000 and Kollicoat IR, reduces the stabiliy time of the vesicles in the

solution. Because the mixtures have hydrophilic and hydrophobic characteristics, they

play an important role in connecting the vesicles, causing the distance of the vesicle to

decrease, thereby enhancing the probability for vesicle fusion. The hydration repulsion of

each vesicle becomes powerless with their help and, meanwhile, the hydrophobic

attraction and the attraction of van der Waals forces is enhanced as well.

The permeability of DMPC bilayers of the small vesicles has been analysed by means of

the Stopped Flow method, which was followed by the exchange reaction of F- and SCN2+.

The presence of 10R5 in the vesicles shortens the reaction time of F- and SCN2+, and

apparently the transport of ions through the vesicle bilayers is facilitated by the presence

of 10R5. However, it results conversely in the presence of L35. Both triblock copolymers

contain the same values of EO and PO blocks, but lay with converse position order. The

forces of vesicle bilayers of phospholipids are an interesting topic to investigate in the

future.

131

The mixtures of 0.1% DMPC and DHPC were prepared at different mass ratio behaviours

to form the bicell vesicles in the solution. Furthermore, the stability of the vesicles was

investigated by a DLS as a function of time. The sample MH11 keeps the most stable time

than other samples. The small vesicles of M11 keep around 20 days after extrusion. In the

presence of DHPC reduces the stable time of small unilamellar vesicles of DMPC solution.

Bicellar vesicles are composed of long and short alkyl chain phospholipids. It is not

conclusive to prove that the bicellar viscles have been already formed by DMPC and

DHPC in the solution especially analysed by one method of DLS. The shape and structure

of Bicellar vesicles can be further investigated by other techniques, such as DSC,

because the phospholipids have characteristics of thermotropic transitions. Microscopy

methods are like Cryo-transmission electron microscopy (Cryo-TEM): the direct image can

be seen. The X-ray experiment, like SAXS, provides the information for the phases

behaviour and organization of lipids [110].

The phase transition from the lamellar gel phase Lβ to the fluid Lα phase of DMPC

solutions, which exist as large unilamellar vesicles in solutions, was determined by DSC

where Tm is at 24.3oC and the pretransition temperature is at 14.0oC in the heating

process. The transition state is that the trans-comformation of the hydrocarbon chain of

DMPC turns to gauche-trans-gauche conformation (see Fig. 1-6-2). The Tm of DMPC

solution does not have much influence when the large unilamellar vesicles become small.

However, the entropy decreases when they become small vesicles. The curvature of the

increasing vesicles is caused by the extrusion, and the small pore size of polycarbonate

filter leads to the production of a large curvature effect [91].

The diesterquat CR3099 forms stable vesicles in solutions spontaneously. However, its

size can be reduced by extrusion and these smaller unilamellar vesicles are then stable

for a long time. In the presence of polymers, like 10R5 and Kollicoat IR, the vesicle size is

reduced and this reduction is proportional to the concentration. The presence of

copolymers results in no influence on stable time of reduced small vesicles. They can still

keep this size for a period of time. It is very stable and independent of temperature. The

small vesicles of CR3099, which have been extruded, result in lower viscosity than larger

vesicles. The addition of 10R5 has no influence on the viscosity. This experiment takes

0.5 wt.% CR3099 solution and 0.1 % DMPC as the parent solutions to analyse kinetic

stability thermal property, permeability, viscosity and conductivity. The thickness of both is

determined by a Kratky-Porod model. Tab. 6-1 summarizes the physical and chemical

properties of both small vesicle solutions.

132

Tab. 6-1: Characters of DMPC and CR3099 solution

Phospholipids DMPC

Diesterquat CR3099

Name

1,2Dimyristoyl-sn-Glycero-3-

Phosphocholine

Di-Oleic Acidyl Isopropylester

Dimethylammonium Methosulfate

Structure

OPON+

O-

N+

Phases

transition

Yes

Vesicle size

after

extrusion

70 nm

100 nm

thickness

2.15 nm

2.72 nm

Stability after

extrusion

Yes, one month

Yes, six months

Permeability

Yes

Sediments

Yes

Fusion effect

Yes

Finally, vesicle gels composed of uncharged surfactant TDMAO, ionic surfactant TTABr

and apolar oil 1-Hexanol have been studied with respect to their interaction with

amphiphilic copolymers, with a particular emphasis on the effects on the rheological

behaviour. For these gels the elastic modulus G’ is higher than the viscous modulus G’’.

The increasing amounts of TDMAO, TTABr and 1-Hexanol lead to high elastic properties,

such as the sample of 180 mM TDMAO, 20 mM TTABr and 400 mM 1-Hexanol. The

presence of copolymers, like 10R5, Rewopal 6000 and F108, changes the elastic

properties of each gel solution respectively. Fig. 5-2-8 presents a simple schema of

multilammelar vesicle (MLV) with additives. In this experiment, these are 10R5, Rewopal

6000 and F108. The additives could exist between layers of vesicles. The steadfest MLVs

are improved especially with the addition of Rewopal 6000. Under macroscopic conditions,

the birefringence property can be observed by the tool of cross polarizers. No signals of

birefringence are observed in this experiment for these gel samples. (Some rheology

measurements are not discussed since it is not within the scope of this dissertation.) The

yield stress σ is the point when the gel solution begins to deform as function of shear

rate. They can be further invesigated by properties of conductivity, for the composition of

the gel solution composed of ionic surfactant. The shape and size of the vesicle gels can

be analysed by scattering methods, such as DLS, SAXS and SANS, by microscopy, such

as TEM, the method of microscopy provides the real space image of the vesicle gel

phases [106, 111].

133

7. Appendix

Polar oils and F108 solution measured by Fluorescence spectroscopy

1-Hexanol and 3.6 mm F108

10 15 20 25 30 35 40

1,2

1,3

1,4

1,5

1,6

1,7

1,8

1,9

T/ oC

1-Hexanol

0 mm

10 mm

20 mm

30 mm

40 mm

43 mm

1-Hexanol and 3.6 mm F108 solution

I1/I3

Fig. 7-1: Ratio of I1 and I3 for 1-Hexanol in 3.6 mm F108 as function temperature

1-Hexanol and 7.0 mm F108 solution

0 5 10 15 20 25 30 35 40

1,0

1,2

1,4

1,6

1,8

T/ oC

1-Hexanol

0 mm

40 mm

60 mm

140 mm

300 mm

I1/I3

1-Hexanol and 7.0 mm F108 solution

Fig. 7-2: Ratio of I1 and I3 for 1-Hexanol in 7.0 mm F108 as function temperature

134

Geraniol and 3.6 mm F108

10 15 20 25 30 35

1,0

1,2

1,4

1,6

1,8

2,0

Geraniol

0 mm

1.0 mm

1.5 mm

2.0 mm

3.0 mm

5.0 mm

T/ oC

Geraniol and 3.6 mm F108 solution

I1/I3

Fig. 7-3: Ratio of I1 and I3 for Geraniol in 3.6 mm F108 as function temperature

Toluene and 3.6 mm F108

10 15 20 25 30 35

1,3

1,4

1,5

1,6

1,7

1,8

1,9

T/ oC

Toluene

0 mm

5 mm

10 mm

13 mm

25 mm

I1/I3

Toluene and 3.6 mm F108 solution

Fig. 7-4: Ratio of I1 and I3 for Toluene in 3.6 mm F108 as function temperature

135

Homo copolymer PPO and 3.6 mm F108

10 15 20 25 30 35 40

1,2

1,3

1,4

1,5

1,6

1,7

1,8

1,9

T/ oC

(PO)17

0 mm

5 mm

10 mm

13 mm

16 mm

21 mm

I1/I3

PPO and 3.6 mm F108 solution

Fig. 7-5: Ratio of I1 and I3 for PPO in 3.6 mm F108 as function temperature

136

8. Acknowledgement

I would like to express my gratitude to all those who gave me the possibility to complete

this thesis. I am deeply thankful to my supervisor Prof. Dr. Michael Gradzielski from the

Technical University Berlin whose encouragement, stimulating suggestions and surports

helped me in all the time of research for and writing of this thesis.

My colleagues from Stranski labortorium supported me in my research work. I want to

thank them for all their help, support, interest and beamtime. My friend he looked the last

part of the thesis for English style and grammar, correcting both and offering suggestions

for improvement.

Lastly, I offer my regards and blessings to all of those who supported me in any respect

during the completion of the doctorthesis.

Hsin-yi Liu

137

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10. List of Publication

1. Solubilisation of Oils of Different Polarity in Aqueous Solution of Pluronic

Triblock Copolymers, Hsin-yi Liu. Sylvain Prévost, and Michael Gradzielski Z. Phys.

Chem. 226 (2012) 675-694