RESEARCH ARTICLE
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Real-Time Moni o ing o Pa icle Size in Emulsion
Polyme iza ion: Simul aneous Tu bidi y and Pho on Densi y
Wa e Spec oscopy
Usue Ola z Aspiazu, Susana Gómez, Ma ia Paulis,* and Jose Ramon Leiza*
Pa icle size e olu ion in seeded semiba ch emulsion polyme iza ion is
moni o ed by wo eal- ime moni o ing echniques: online u bidi y
spec oscopy (TUS) and inline pho on densi y wa e spec oscopy (PDWS). An
au oma ic dilu ion sys em ha wi hd aws a sample om he eac o and upon
dilu ion ans e s o he measu emen cell is used o he online TUS analysis.
A PDWS p obe is imme sed in he eac o and collec s inline he sca e ed
ligh di ec ly om he eac ing la ex. The pa icle sizes e ie ed om TUS and
PDWS a e compa ed o offline dynamic ligh sca e ing (DLS) alues. The
pa icle size ob ained by TUS is close o he in ensi y-a e age pa icle size
ob ained offline by DLS, while he pa icle size ob ained by PDWS lies close
o he numbe -a e age pa icle size om DLS.
1. In oduc ion
Polyme la exes a e wa e bo ne polyme dispe sions ha a e
used o o mula e all kind o pain s, coa ings, adhesi es, and a
my iad o addi i es o a wide ange o applica ions.[1–3]Pa i-
cle size and pa icle size dis ibu ion (PSD) a e key cha ac e -
is ics o polyme la exes,[3]as hey affec he heology (e.g., is-
cosi y) o he dispe sion and i s film o ma ion, among o he s,
which a e impo an o con ol he p ocess and he applica ion
p ope ies o he la exes.[3]The e o e, a obus and efficien syn-
he ic p ocess should ensu e he ep oducibili y o hese cha ac-
e is ics du ing he p ocess o a oid off-spec p oduc s and eco-
nomic loses. Hence, eal- ime moni o ing o he pa icle size is
necessa y o be able o implemen eal- ime (close-loop) con ol
U. O. Aspiazu, M. Paulis, J. R. Leiza
POLYMAT, Kimika Aplika ua Saila, Kimika Fakul a ea
Uni e si y o he Basque Coun y UPV/EHU
Joxe Ma i Ko a Zen oa, Donos ia-San Sebas ián 20018, Spain
E-mail: [email p o ec ed];[email p o ec ed]
S. Gómez
IRIS Technology Solu ions SL. Ca e e a Esplugues Local 39-41
Co nellá de Llob ega , Ba celona 08940, Spain
The ORCID iden ifica ion numbe (s) o he au ho (s) o his a icle
can be ound unde h ps://doi.o g/10.1002/ma c.202400374
© 2024 The Au ho (s). Mac omolecula Rapid Communica ions
published by Wiley-VCH GmbH. This is an open access a icle unde he
e ms o he C ea i e Commons A ibu ion-NonComme cial-NoDe i s
License, which pe mi s use and dis ibu ion in any medium, p o ided he
o iginal wo k is p ope ly ci ed, he use is non-comme cial and no
modifica ions o adap a ions a e made.
DOI: 10.1002/ma c.202400374
s a egies. This is why a lo o effo has
been de o ed o de elop eal- ime online o
inline au oma ic pa icle size cha ac e iza-
ion echniques.[3,4]
Pa icle size cha ac e iza ion ech-
niques can be clus e ed in h ee main
g oups: sca e ing echniques (e.g., dy-
namic ligh sca e ing (DLS) and s a ic
ligh sca e ing (SLS), espec i ely), lase
diff ac ion, pho on densi y wa e spec-
oscopy (PDWS) o u bidi y spec oscopy
(TUS)); ac iona ion echniques (e.g., cap-
illa y hyd odynamic ac iona ion (CHDF),
analy ical cen i uga ion o field flow ac-
iona ion); and coun ing echniques (e.g.,
ansmission elec on mic oscopy (TEM),
pa icle acking analysis, op ofluidic o ce induc ion (OF2i), o
ligh obscu a ion). Mos o hem a e offline analysis echniques,
wha means no only ha samples need o be wi hd awn and
manually p epa ed o he analysis, bu also ha he ime delay
o ge he esul s is la ge, going om ew minu es (DLS case) o
some hou s (TEM case). Thus, online/inline pa icle size cha ac-
e iza ion echniques can be used o o e come hese limi a ions,
as ime delays a e subs an ially educed and manual p epa a ions
a e a oided.
Few echnologies based on ligh sca e ing, ul asonic p op-
e ies, NIR o Raman spec oscopy, ocus beam eflec ance, o
op ofluidic o ce induc ion ha e been used o de e mine pa i-
cle sizes in eal ime, bu no all o hem a e able o each he
sub-mic ome e pa icle size ange.[4–14]Mo eo e , many o hem
wo k in e y dilu ed media; hus, he e is a need o au oma ically
dilu e he sample be o e he analysis (online analysis), which can-
no be accep able o ce ain p ocesses, due o he clogging ha
could occu inside he dilu ion sys em. Fu he mo e, he high di-
lu ions needed could lead o la ge ime delays be ween sampling
and acquisi ion o he esul s.[3]
The online TUS and he inline PDWS a e wo o he a ailable
eal- ime echnologies o moni o he pa icle size o wa e bo ne
polyme ic dispe sions. Bo h a e sca e ing-based echniques and
ha e been p e iously assessed o online and inline moni o he
pa icle size e olu ion du ing emulsion polyme iza ions.[15–23]
Howe e , we a e no awa e ha bo h echniques ha e e e been
used simul aneously o moni o emulsion polyme iza ion p o-
cess and hei pe o mance compa ed wi h a common e e -
ence echnique like DLS. Thus, in his wo k, bo h echniques
will be used as online/inline echnologies (TUS and PDWS,
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espec i ely) o moni o seeded semiba ch emulsion polyme iza-
ion p ocesses o ac ylic copolyme s.
In he p esen s udy, a comme cial calo ime ic eac o is
equipped wi h bo h spec oscopic echnologies including an au-
oma ic dilu ion sys em o he u bidime ic echnique. Thus,
simul aneous eal- ime pa icle size measu emen s a e ga h-
e ed du ing he seeded semiba ch emulsion copolyme iza ion
o me hyl me hac yla e (MMA)/n-bu yl ac yla e (BA)/me hac ylic
acid (MAA) eac ion. In addi ion, he ob ained esul s a e com-
pa ed o pa icle sizes ob ained offline by DLS measu emen s.
Fi s , a b ie desc ip ion o he measu emen p inciples o bo h
echniques is gi en. Then, he no el eac ion se -up and he ex-
pe imen al de ails o he emulsion polyme iza ion ca ied ou a e
p esen ed, ollowed by he moni o ing o he expe imen and he
compa ison and discussion o he esul s.
1.1. Tu bidi y Spec oscopy
Tu bidi y spec oscopy is a single sca e ing-based pa icle size
measu emen echnique.[24–26]The in ensi y o he ansmi ed
ligh o a sample is measu ed o e a ange o wa eleng hs and
om his in o ma ion, i he sample is dilu ed enough, he pa i-
cle size can be e ie ed.
F om he wa eleng h-dependen ansmission cu e, he u -
bidi y cu e is calcula ed by means o Equa ion (1)
𝜏(𝜆i)=1
zln [I0(𝜆i)∕I (𝜆i)] (1)
whe e 𝜏(𝜆i) is he u bidi y a a ce ain wa eleng h, I0(𝜆i)andI (𝜆i)
a e he in ensi ies o he emi ed and he de ec ed ligh s ( espec-
i ely) a 𝜆iwa eleng h, 𝜆iis he wa eleng h o he ligh used o
he analysis, and zis he dis ance be ween he emission and he
de ec ion poin s.
Se e al me hods can be used o e ie e he pa icle size om
he u bidi y spec a.[23,27–29]One o hem is he wa eleng h ex-
ponen me hod,[23,24]whe e a pa ame e called wa eleng h expo-
nen is calcula ed om he u bidi y o e he wa eleng h da a by
means o Equa ion (2)
𝜏(𝜆0)=k𝜆0
−𝜔(2)
whe e 𝜏(𝜆0) is he u bidi y o he sample a 𝜆0wa eleng h, being
𝜆0 he wa eleng h whe e he analyzed wa eleng h ange is cen-
e ed, 𝜔is he wa eleng h exponen , and kis he p opo ionali y
ac o be ween he u bidi y and he wa eleng h exponen .
The wa eleng h exponen is di ec ly ela ed o he size o
he pa icles ha a e in he medium. Theo e ically, Mie heo y
can be used o desc ibe he ela ion be ween he wa eleng h
exponen and pa icle size o each wa eleng h. Al e na i ely,
his ela ion can be de e mined expe imen ally by measu ing
he u bidi y o la ex samples o known pa icle size (e.g., mea-
su ed DLS) and app oxima ing he wa eleng h exponen om
he slope o he log 𝜏 e sus log 𝜆cu es ob ained o each la-
ex; namely, a calib a ion cu e ha ela es 𝜔and dpcan be buil
o a gi en ype o la ex.[23]This calib a ion cu e was ob ained
o he MMA/BA/MAA copolyme la ex syn hesized in his wo k
and i is shown in he Suppo ing In o ma ion. Simila calib a-
ion cu es ha e been ob ained co ela ing Raman o NIR spec-
a wi h pa icle size by p incipal componen models in emulsion
polyme iza ion sys ems.[4–12]
As men ioned abo e, single sca e ing condi ions ha e o be
ulfilled o each an app op ia e esul by TUS. I he concen a-
ion o he dispe sed phase is high, as in he ypical seeded semi-
ba ch emulsion polyme iza ions used o p oduce comme cial la-
exes o coa ings and adhesi es, he TUS measu emen cell can-
no be in oduced in he eac ion mix u e. Ins ead, samples a e
wi hd awn om he eac o and dilu ed be o e analyzing hem
in he TUS cell.[19,21]Wi h he aim o au oma izing his s ep, an
au oma ic dilu ion sys em is connec ed o he TUS equipmen ,
which is able o each he equi ed single sca e ing condi ion by
eedback con ol based on he ansmission o he sample a di -
e en wa eleng hs. Addi ional de ails abou he dilu ion sys em
p o ided by IRIS a e p esen ed in he Suppo ing In o ma ion.
A so wa e was de eloped by IRIS Technology Solu ions o wo k
wi h i s au oma ic dilu ion sys em.
1.2. Pho on Densi y Wa e Spec oscopy
PDWS is an inline pa icle size cha ac e iza ion echnology de-
eloped by he Uni e si y o Po sdam (PU) and pho on densi y
wa e analy ics (PDWA), ha is able o measu e he pa icle size
o highly concen a ed dispe sions. The p obe ha collec s he
da a is composed by se e al fibe s ha can ac as emission o
de ec ion fibe s. A ligh is emi ed om he de ec o fibe and a -
e colliding wi h he pa icles ha a e in he medium, he ligh
eaches he de ec o fibe . The emi ed and he de ec ed signals
p esen a diffe ence no only in he ampli ude o he in ensi y
o he ligh (which dec eases in each collision), bu also in i s
phase. Measu ing he ampli ude and he phase shi s a diffe en
p obe dis ances and lase modula ion equencies, he in ensi y
and phase cons an s can be calcula ed, om which he abso p ion
and he educed sca e ing coefficien s o he dispe sion can be
de e mined. F om he educed sca e ing da a, pa icle size can
be e ie ed by means o Equa ion (3) ( o monodispe sed sphe -
ical pa icles)
𝜇′
s=3𝜑𝜋Qs
2dp
1
∫
−1
(cos (𝜃)) S(𝜃,𝜑)[1−cos (𝜃)]dcos(𝜃)(3)
whe e 𝜇′
sis he educed sca e ing coefficien , dpis he pa icle
size o he dispe sed phase, Qsis he sca e ing efficiency, is he
phase unc ion, S(𝜃,𝜑) is he s uc u al ac o , 𝜃is he sca e -
ing angle, and 𝜑is he olume ac ion o he dispe sed phase,
which is ela ed o he solids’ con en o he medium. A de ailed
desc ip ion o he PDWS heo y can be ound elsewhe e.[30–33]
2. Expe imen al Sec ion
2.1. Ma e ials
Monome s we e used as ecei ed: MMA (Quimid oga), BA
(Quimid oga), and MAA (Ald ich). Sodium dodecyl sul a e (SDS,
Ald ich) and Dow ax 2A1 (kindly supplied by Dow Chemical)
we e used as emulsifie s. Ammonium pe sul a e (APS, Ald ich)
was used as he ini ia o . As con inuous medium du ing he poly-
me iza ion and o sample dilu ion (DLS and TUS) deionized
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(DI) high-pu i y wa e ob ained h ough a Me ck Millipo e sys-
em (DI-wa e ) was used. Wa e conduc i i y was lowe han 1 μS
cm−1in all cases.
2.2. Syn hesis o he MMA/BA/MAA Copolyme La ex
I was wo h men ioning ha ab ini io ba ch emulsion polyme -
iza ions canno be moni o ed wi h TUS and PDWS. The eason
is ha pa icle nuclea ion yields pa icle sizes (below 50 nm) ha
a e ou o he ange ha can be cap u ed nonambiguously om
TUS, and u he mo e, o PDWS and due o he low solids’ con-
en achie ed du ing he nuclea ion p ocess, he sca e ed ligh
is los and hence i canno be applied he mul iple sca e ing ap-
p oach used in he PDWS.
The e o e, a seeded semiba ch emulsion polyme iza ion eac-
ion was simul aneously moni o ed by TUS and PDWS equip-
men s. Fi s , a seed was syn hesized and a e he pa icles o he
seed we e g own un il he a ge ed pa icle size ( his las s ep was
moni o ed simul aneously by TUS and PDWS). A seed wi h a -
ge mola composi ions o MMA/BA 50/50 w % was syn hesized
ba chwise. Fo his aim, wa e , comonome s, and emulsifie we e
mixed in he eac o . A sho o ini ia o was added once he mix-
u e eached a empe a u e o 85 °C. The mix u e was le o e-
ac o 4 h. The o mula o he syn hesis o he seed (S1) can be
ound in Table SI1 (Suppo ing In o ma ion).
The seeded semiba ch emulsion polyme iza ion eac ion ha
was simul aneously moni o ed by TUS and PDWS was pe -
o med as ollows: fi s , a ce ain amoun o seed la ex plus wa e
was loaded in he eac o o ha e a solids’ con en o 3%. A e -
wa d, he mix u e was hea ed o 85 °C, he eac ion empe a u e.
A e eaching he eac ion empe a u e, monome s and ini ia o
we e ed o he eac o in wo sepa a ed eeding s eams du ing
180 min a a cons an flow a e. The ecipe o he eac ion (SB1)
can be ound in Table SI2 (Suppo ing In o ma ion). Finally, he
la ex was main ained a he eac ion empe a u e o 30 min o
emo e he esidual monome .
2.3. Desc ip ion o he Se -Up and he Analysis Equipmen
A 1 L calo ime y eac o (RC1e) om Me le Toledo was used o
pe o m all he eac ions, equipped wi h a jacke ed glass eac o
fi ed wi h he ollowing fi ings: a sampling de ice o wi hd aw
he samples o TUS measu emen s, he inline PDWS p obe, a
ni ogen inle , eeding inle s, a P -100 p obe, and a s ainless s eel
ancho ype s i e . iCon ol RC1e So wa e was used o con ol
he eac ion empe a u e and he inle flow a es o semicon in-
uous eeds. Samples we e wi hd awn du ing he eac ion o ana-
lyze he e olu ion o pa icle size offline by DLS (e e y 10–15 min
du ing he fi s 60 min o he eac ion and e e y 20–30 min a e
ha ime).
A PDWS equipmen de eloped by PDW Analy ics
GmbH (Po sdam, Ge many) was used o he pa icle size
moni o ing.[15,22,33,34]The PDWS was equipped wi h ou lase s
o 636, 778, 855, and 973 nm wa eleng hs, 27 possible dis ances
om 3 o 25 mm, and 41 possible equencies om 10 o
610 MHz. To calcula e he pa icle size, a so wa e de eloped by
innoFSPEC Po sdam om he Uni e si y o Po sdam was used,
based on Mie heo y and he heo y o dependen sca e ing.
TUS equipmen de eloped by IRIS Technology Solu ions
(Ba celona, Spain) was used, which consis s o a con inuous spec-
ome e and is composed o a p obe, an elec ical cabine , and a
compu e wi h a dedica ed so wa e o da a p ocessing. As men-
ioned abo e, u bidi y should be measu ed a condi ions wi h no
significan mul iple sca e ing, wha means ha samples wi h-
d awn om he emulsion polyme iza ion expe imen s need o
be dilu ed.[18–21]The dilu ion sys em, de eloped by IRIS in col-
labo a ion wi h POLYMAT, used o his wo k is a dilu ion sys-
em wi h an au oma ic decision making so wa e o selec he ap-
p op ia e dilu ion le el by analyzing he ansmission cu es. A
ske ch o he se up and an image o he ac ual lab se up used o
he simul aneous analysis a e shown in Figu e 1.
A Ze asize Nano Se ies (Mal e n Ins umen ) DLS was used
as e e ence echnique in his wo k. Fo he analysis, he la ex
was dilu ed in DI wa e un il an a enua ion numbe o 6–7 was
achie ed a 4.65 mm posi ion o ensu e single sca e ing condi-
ions. DLS measu emen s we e ca ied ou a oom empe a u e,
and h ee epea ed measu emen s we e ca ied ou o each sam-
ple. All e e ence pa icle sizes shown in his wo k we e bo h
in ensi y- and numbe -a e age pa icle sizes measu ed by DLS.
3. Resul s and Discussion
A seeded semiba ch emulsion copolyme iza ion (composi ion
MMA/BA/MAA: 51/47/2 w %) eac ion (SB1) was used o simul-
aneously assess he pe o mance o bo h TUS and PDWS ech-
nologies o moni o pa icle size g ow h. Reac ion SB1 aims o
p oduce a la ex wi h an a e age pa icle size o 225 nm and a
solids’ con en o 45 w % s a ing om a seed (S1, see he Sup-
po ing In o ma ion) wi h a pa icle size o 67 nm (in ensi y-
a e age size) and 3% o solids’ con en . Figu e 2p esen s he
ansmission cu es ob ained o he samples online analyzed by
TUS du ing SB1 emulsion polyme iza ion eac ion.
F om he ansmission cu es p esen ed in Figu e 2, he wa e-
leng h exponen was calcula ed as explained in he p e ious sec-
ion, ge ing o he ollowing esul s (Figu e 3).
Figu e 3shows ha he wa eleng h exponen dec eases du -
ing he eac ion, which, acco ding o he calib a ion cu e used,
p edic s an inc ease in he pa icle size, as i is expec ed in
his seeded semiba ch emulsion polyme iza ion. F om he wa e-
leng h exponen alues p esen ed in Figu e 3and by means o
he calib a ion cu e explained abo e (which can also be ound
in Figu e SI1 in he Suppo ing In o ma ion), he pa icle size
was e ie ed (see Figu e 5).
Figu e 4p esen s he ime e olu ion o he educed sca e ing
coefficien ob ained by inline PDWS analysis du ing SB1 emul-
sion polyme iza ion eac ion.
Figu e 4shows ha he educed sca e ing coefficien in-
c eases du ing he syn hesis o all he lase wa eleng hs. A he
beginning o he eac ion, he solids’ con en is e y low; hus, he
mul iple sca e ing condi ions a e no ully accomplished, and
he changes in he educed sca e ing coefficien can ha dly be
de ec ed, bu a e 20 min, he sample is u bid enough (bo h pa -
icle size and solids’ con en inc eased) and he en i e p ocess can
be moni o ed. Mo eo e , i can be seen ha o he analyzed pa -
icle size ange, he smalle he wa eleng h o he lase ligh , he
highe he sensi i i y o he changes occu ing in he eac o .[22]
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Figu e 1. Se up o simul aneous PDWS and TUS analyses o emulsion polyme iza ion p ocesses: a) scheme and b) pho og aph o he lab se up.
The pa icle size e olu ion was e ie ed, om he abo e p e-
sen ed wa eleng h exponen (Figu e 3) and educed sca e ing
coefficien e olu ions (Figu e 4), using he wa eleng h exponen
me hod and he adia ion anspo heo y, Mie heo y, and de-
penden sca e ing app oaches, espec i ely, as discussed in u -
he de ail in o he wo ks.[16,22,23,25,30]The esul s ob ained by he
simul aneous analysis and hei compa ison o offline DLS e e -
ence measu emen s a e displayed in Figu e 5.
400 500 600 700 800 900 1000
0
20
40
60
80
100
0 min
8 min
20 min
30 min
40 min
50 min
60 min
75 min
90 min
107 min
120 min
141 min
160 min
180 min
%/noissimsna T
Wa eleng h /nm
Figu e 2. T ansmission cu es o he samples online analyzed by TUS us-
ing he au oma ic dilu ion sys em du ing SB1 emulsion polyme iza ion
eac ion (samples 60 and 120 min do no ulfill he lowe limi c i e ia,
because he maximum ime o dilu ion se was no enough o each he
condi ions).
All he echniques, eal- ime online TUS and inline PDWS and
offline DLS, cap u ed he g ow h o he pa icle size wi h eac-
ion ime, which ma ches he heo e ical e olu ion o he pa icle
g ow h in he absence o seconda y nuclea ion o agg ega ions
(see Figu e SI3 in he Suppo ing In o ma ion). Howe e , he e
a e some diffe ences ha need a co ec in e p e a ion o he plo -
ed da a. No e ha o he offline DLS analysis wo a e ages a e
p o ided; he in ensi y-a e age, which is he na u al a e age ob-
ained om he DLS and he numbe a e age ha is calcula ed
om he cumulan me hod assuming a unimodal Gaussian dis-
ibu ion o he dispe sed pa icle sizes (DLS pa icle size and
0 30 60 90 120 150 180 210
2,6
2,8
3
3,2
3,4
3,6
3,8
nenopxeh gnele aW
Reac ion ime /min
Figu e 3. Wa eleng h exponen e olu ion du ing SB1 emulsion polyme -
iza ion eac ion.
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0 30 60 90 120 150 180 210
0
1
2
3
4
5
μ
s
' 636
μ
s
' 778
μ
s
' 855
μ
s
' 973
1-mm/ neici eoCgni e acSdecudeR
Reac ion ime /min
Figu e 4. Reduced sca e ing coefficien e olu ion ob ained by inline
PDWS du ing SB1 emulsion polyme iza ion eac ion.
PDI alues can be ound in Table SI3 in he Suppo ing In o ma-
ion). In e es ingly, he e olu ion o he pa icle sizes calcula ed
om he eal- ime spec oscopic echniques is close o diffe -
en a e age alues; TUS pa icle sizes a e in easonable ag ee-
men wi h in ensi y-a e age sizes o DLS, while PDW pa icle
sizes a e close o he numbe -a e age sizes o DLS. The ma ch-
ing o he TUS pa icle size and in ensi y-a e age pa icles sizes
o DLS was expec ed, because he calib a ion cu e ha ela es
he wa eleng h exponen and pa icle size (see Figu e SI1 in he
Suppo ing In o ma ion) was buil using in ensi y-a e age pa i-
cle sizes measu ed by DLS. Fo he PDWS, he e is no calib a ion
cu e o e ie e he pa icle size. The pa icle size is ob ained
om he heo e ical dependence o he educed sca e ing wi h
0 30 60 90 120 150 180 210
0
40
80
120
160
200
240
d
PDW, 636 nm
d
TUS, WE exp.
d
DLS, I
d
DLS, N
mn/ e emaidelci aP
Reac ion ime /min
Figu e 5. Real- ime online (TUS) and inline (PDWS) measu emen s o
he e olu ion o he pa icle size du ing he seeded semiba ch emul-
sion copolyme iza ion SB1 and compa ison wi h he offline numbe - and
in ensi y-a e age pa icle sizes calcula ed by DLS.
he pa icle size as explained elsewhe e.[30,35]The only inpu pa-
ame e s a e he physical p ope ies o he polyme pa icles (in
his wo k he wa eleng h-dependen e ac i e index and he den-
si y o he MMA/BA/MAA copolyme ) and he solids’ con en
o he dispe sion. The e o e, he pa icle size measu ed can be
conside ed as he PDWS a e age. In e es ingly, his a e age (ob-
ained om he educed sca e ing ob ained wi h he lase wi h
lowes wa eleng h o he p obe; 636 nm, he mos sensi i e one)
seems o be in excellen ag eemen wi h he numbe -a e age pa -
icle size measu ed by DLS. In li e a u e, diffe en compa isons
can be ound, bu he e is no a consensus abou which a e age
is p o ided by PDWS.[15–17,22,35]
4. Conclusions
In he p esen wo k, an emulsion polyme iza ion p ocess o p o-
duce an MMA/BA/MAA copolyme la ex was moni o ed by si-
mul aneously using TUS and PDWS equipmen s. A calo ime e
eac o was equipped wi h bo h spec oscopic ins umen s. Fo
PDWS, a p obe was in oduced in o he eac o medium allow-
ing inline measu emen s, while, o TUS, an au oma ic dilu ion
sys em was buil -in ha was able o ex ac and dilu e he sample
be o e he analysis in he measu emen cell.
Thus, eal- ime inline and online pa icle size measu emen s
we e ob ained du ing he seeded semiba ch emulsion polyme -
iza ion eac ion. The pa icle size o he moni o ed p ocess
changed om he ini ial 67 nm o he seed (and 3 w % solids’ con-
en ) o a ound 200 nm (and 45 w % solids’ con en ) o he final
la ex. Bo h echniques p edic ed well he g ow h o he seed pa -
icles. Howe e , he absolu e alue calcula ed by each echnique
ma ches be e wi h diffe en a e age alues calcula ed offline by
DLS.
Suppo ing In o ma ion
Suppo ing In o ma ion is a ailable om he Wiley Online Lib a y o om
he au ho .
Acknowledgemen s
The au ho s would like o hank he financial suppo om he Basque
Go e nmen (IT-1525-22), Eu opean Union‘s Ho izon 2020 Resea ch and
Inno a ion P og amme o he unding ecei ed h ough he NanoPAT
p ojec (G an ag eemen No. 862583), IRIS Technology Solu ions SL o
he TUS equipmen , PDW Analy ics o he PDW equipmen , and innoF-
SPEC depa men om Po sdam Uni e si y o he aining and he help
du ing he s udy.
Conflic o In e es
The au ho s decla e no conflic o in e es .
Da a A ailabili y S a emen
The da a ha suppo he findings o his s udy a e a ailable om he co -
esponding au ho upon easonable eques .
Mac omol. Rapid Commun. 2024,45, 2400374 2400374 (5 o 6) © 2024 The Au ho (s). Mac omolecula Rapid Communica ions published by Wiley-VCH GmbH
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www.ad ancedsciencenews.com www.m c-jou nal.de
Keywo ds
emulsion polyme iza ion, PDWS, polyme pa icle size, eal- ime moni o -
ing, TUS
Recei ed: May 23, 2024
Re ised: June 28, 2024
Published online: July 17, 2024
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