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The chemical and electrochemical oxidative polymerization of 2-amino-4-tert-butylphenol

Abstract

[EN] Poly(2-amino-4-tert-butylphenol), poly(2A-4TBP), was synthesized from monomer aqueous solution using either electrochemical or chemical oxidation procedures. Several spectroscopic characterization techniques were employed to gain information on the chemical structure and redox behavior of the obtained materials. It was found that the chemical polymerization product could be described as an oligomer mixture containing up to 16 monomer units. In parallel to other polymers derived from o-aminophenol, phenoxazine rings constitute also the basic structure of poly(2A-4TBP). In addition, the occurrence of N-N couplings, which are favored by the presence of the voluminous tert-butyl substituent, seems also relevant. No significant structural differences were found between the chemically or electrochemically synthesized materials. © 2016 Published by Elsevier Ltd.

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The chemical and electrochemical oxidative polymerization of 2-amino-4-tert-butylphenol

Author: Abidi, Maali,López-Bernabeu, Sara,Huerta, Francisco,Montilla-Jiménez, Francisco,Besbes-Hentati, Salma,Morallón, Emilia
Publisher: Elsevier
Year: 2016
DOI: 10.1016/j.electacta.2016.07.060
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Abidi, M.; López-Be nabeu, S.; Hue a, F.; Mon illa-Jiménez, F.; Besbes-Hen a i, S.;
Mo allón, E. (2016). The chemical and elec ochemical oxida i e polyme iza ion o 2-amino-
4- e -bu ylphenol. Elec ochimica Ac a. 212:958-965. doi:10.1016/j.elec ac a.2016.07.060
h p://dx.doi.o g/10.1016/j.elec ac a.2016.07.060
Else ie
Accep ed Manusc ip
Ti le: The chemical and elec ochemical oxida i e
polyme iza ion o 2-amino-4- e -bu ylphenol
Au ho : M. Abidi S. L´
opez-Be nabeu F. Hue a F. Mon illa S.
Besbes-Hen a i E. Mo all´
on
PII: S0013-4686(16)31565-1
DOI: h p://dx.doi.o g/doi:10.1016/j.elec ac a.2016.07.060
Re e ence: EA 27675
To appea in: Elec ochimica Ac a
Recei ed da e: 20-2-2016
Re ised da e: 26-4-2016
Accep ed da e: 11-7-2016
Please ci e his a icle as: M.Abidi, S.L´
opez-Be nabeu, F.Hue a, F.Mon illa,
S.Besbes-Hen a i, E.Mo all´
on, The chemical and elec ochemical oxida i e
polyme iza ion o 2-amino-4- e -bu ylphenol, Elec ochimica Ac a
h p://dx.doi.o g/10.1016/j.elec ac a.2016.07.060
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The chemical and elec ochemical oxida i e polyme iza ion o 2-amino-4-
e -bu ylphenol
M. Abidi1,2, S. López-Be nabeu2, F. Hue a3, F. Mon illa2, S. Besbes-Hen a i1, E. Mo allón2
1Labo a oi e de Chimie des Ma é iaux, Facul é des Sciences de Bize e. 7021, Za zouna
Uni e si é de Ca hage, Tunisie.
2Dep . Química Física e Ins i u o Uni e si a io de Ma e iales, Uni e sidad de Alican e, Ap.
99, E-03080, Alican e, Spain
3Dep . Ingenie ia Tex il y Papele a, Uni e si a Poli ecnica de Valencia, Plaza Fe andiz y
Ca bonell, 1. E-03801, Alcoy, Spain
Abs ac
Poly(2-amino-4- e -bu ylphenol), poly(2A-4TBP), was syn hesized om monome aqueous
solu ion using ei he elec ochemical o chemical oxida ion p ocedu es. Se e al spec oscopic
cha ac e iza ion echniques we e employed o gain in o ma ion on he chemical s uc u e and
edox beha io o he ob ained ma e ials. I was ound ha he chemical polyme iza ion
p oduc could be desc ibed as an oligome mix u e con aining up o 16 monome uni s. In
pa allel o o he polyme s de i ed om o-aminophenol, phenoxazine ings cons i u e also he
basic s uc u e o poly(2A-4TBP). In addi ion, he occu ence o N-N couplings, which a e
a o ed by he p esence o he oluminous e -bu yl subs i uen , seems also ele an . No
signi ican s uc u al di e ences we e ound be ween he chemically o elec ochemically
syn hesized ma e ials.
Keywo ds: elec ochemical polyme iza ion; in si u FTIR; polyaminophenol
2
1. In oduc ion
Aminophenols cons i u e an in e es ing class o compounds o elec opolyme iza ion
owing o he p esence o eac i e amino and hyd oxyl uni s. I has been epo ed ha he
ela i e posi ion o hese uni s a he a oma ic ing plays a signi ican ole in he
elec ochemical eac i i y o he molecule and, consequen ly, he elec ochemical beha io o
he h ee posi ional aminophenol isome s, o ho-, me a- and pa a-, is qui e di e en [1–3] .
Despi e some ea ly con o e sy on he o ma ion, o no , o polyme ic ilms om he
elec ochemical oxida ion o p-aminophenol, i seems now p o ed ha in aqueous media he
monome can be elec opolyme ized o yield complex oligome ic p oduc s whose chemical
s uc u e is s ongly dependen on he pH o he wo king solu ion [4]. The elec o-oxida ion o
m-aminophenol has been sca cely in es iga ed because i yields an elec oinac i e polyme
ha blocks he elec ode su ace and shows a c osslinked s uc u e simila o polyphenol [3,5].
On he con a y, i is well documen ed ha o-aminophenol can be elec ochemically
polyme ized in acidic medium o yield an elec oac i e polyme ic ma e ial ha shows
phenoxazine ladde s uc u es [3,6]. I was also sugges ed ha he p oduc s o med upon o-
aminophenol elec ochemical oxida ion depend on he pH o he polyme iza ion solu ion [7]
al hough i is wo h no ing ha simila s uc u e and p ope ies can be ob ained ega dless o
he polyme iza ion me hod employed, ei he chemical o elec ochemical [1].
Compa isons ha e been also made in he li e a u e be ween chemical and
elec ochemical polyme iza ion p oduc s ob ained om o he a oma ic anilines, wi h special
a en ion paid o diamines [8]. I is usually ound ha he chemical polyme iza ion me hods
esul in highe polyme yields al hough oligome ic by-p oduc s a e di icul o emo e om
he eac ion mix u e. On he o he hand, elec ochemical polyme iza ion o e s he ad an age
ha he ine con ol o he anodic po en ial a oids polyme o e oxida ion and, consequen ly,
ma e ials wi h less de ec s can be isola ed on he elec ode su ace. The o ma ion o non-
conduc ing ilms upon elec ochemical oxida ion could p e en polyme g ow h and such a
possibili y should be aken in o accoun mos ly, al hough no exclusi ely, in expe imen s
conduc ed in neu al and alkaline media.
Chemical and elec ochemical polyme iza ion o alkyl ing-subs i u ed anilines has
a ac ed in e es because o he possibili y o imp o e he poo solubili y o unmodi ied
polyaniline and, besides, o in es iga e he e ec o blocking speci ic ing polyme iza ion
3
si es wi h elec on-dono subs i uen s [9–11]. Howe e , o he bes o ou knowledge, he e is
s ill no epo dealing wi h he chemical o elec ochemical polyme iza ion o alkyl ing-
subs i u ed aminophenols. In he p esen wo k, an a emp has been made o syn hesize a
polyme om bo h ou es and o analyze he e ec o he p esence o a oluminous alkyl
g oup on he well-s udied polyme iza ion p ocess o aminophenols. I is known ha he
p esence o bulky g oups a ached o he a oma ic ing may a oid ππ-s acking be ween icinal
chains o he esul ing polyme and his could lead o an imp o emen in solubili y and
p ocessabili y o he esul ing ma e ial. To achie e hese goals, 2-amino-4- e -bu ylphenol
(2A-4TBP) has been selec ed as he monome species and di e en spec oscopic echniques
ha e been applied o he cha ac e iza ion o he oxida i e polyme iza ion p oduc s.
2. Expe imen al
The solu ions employed o polyme iza ion we e 1.0 M HClO4, p epa ed om Me ck
Sup apu concen a ed acid and 18.2 M cm wa e ob ained om an Elga Labwa e Pu elab
sys em. 2-amino-4- e -bu ylphenol monome was pu chased om Me ck. Ammonium
pe sul a e, om Me ck, was used as he oxidan o chemical polyme iza ion.
Cyclic ol amme y expe imen s we e ca ied ou in a con en ional h ee-elec ode
cell unde N2 a mosphe e. The wo king elec odes used we e ei he pla inum o ITO and a
pla inum wi e was used as he coun e elec ode in all cases. All po en ials we e measu ed
agains he e e sible hyd ogen elec ode (RHE) imme sed in he wo king solu ion h ough a
Luggin capilla y. Cyclic ol ammog ams we e eco ded a a cons an sweep a e o 50 mV s-1
and a oom empe a u e. The polyc ys alline pla inum elec odes we e he mally cleaned and
subsequen ly p o ec ed om he labo a o y a mosphe e by a d ople o ul apu e wa e . ITO
elec odes we e cleaned wi h ace one and ul apu e wa e . Chemically p oduced polyme s
we e deposi ed on he wo king elec odes by cas ing a small olume o suspension con aining
1 mg mL-1 ma e ial in THF sol en .
In si u UV–Vis spec a o polyme s we e eco ded wi h a V-670 spec ome e om
JASCO, which is equipped wi h a double monoch oma o sys em and a pho omul iplie ube
de ec o . A Nicole 5700 spec ome e equipped wi h a ni ogen-cooled MCT de ec o was
employed o he in si u FTIR expe imen s. The wo king P disc elec ode was moun ed on a

4
glass ube and i s 1.0 cm2 su ace was mi o -polished using alumina powde . The
spec oelec ochemical cell was made o glass and was p o ided wi h a p isma ic CaF2
window be eled a 60°. Spec a we e collec ed a 8 cm-1 esolu ion in D2O sol en ( om
Ald ich wi h 99.9% D-a om pu i y) and a e p esen ed as R/R. XPS spec a we e eco ded
wi h a VG-Mic o ech Mul ilab 3000 elec on spec ome e using a non-monoch oma ized
Mg-Ka (1253.6 eV) adia ion sou ce o 300 W and a hemisphe ic elec on analyze equipped
wi h nine channel on elec on mul iplie s. The p essu e o he analysis chambe du ing he
scans was abou 5×10-7 N m-2. A e he su ey spec a we e ob ained, highe esolu ion scans
we e pe o med a pass ene gy o 50 eV. The in ensi ies o he di e en con ibu ions we e
ob ained by means o he calcula ion o he in eg al one o each peak, a e ha ing elimina ed
he baseline wi h S o m and adjus ing he expe imen al cu es o a combina ion o Lo en z
(30%) and Gaussian (70%) lines. All he binding ene gies we e e e ed o he line o he C 1s
o 284.4 eV, ob aining alues wi h a p ecision o ±0.2 eV. The high- esolu ion mass
expe imen s we e pe o med in a MICROMASS Au ospec spec ome e .
3. Resul s and discussion
3.1. Elec ochemically polyme ized 2A-4TBP
Fig. 1 illus a es he cyclic ol amme y cu es eco ded o a polyc ys alline pla inum
elec ode imme sed in 0.1 M HClO4 + 15 mM 2A-4TBP solu ion. The oxida ion o he
monome ic species s a s a 0.76 V and, as deduced om he high slope o he ol amme ic
cu e, is kine ically a o ed du ing he i s ol amme ic sweep. The oxida ion peak is
cen e ed a 0.87 V and, h ough he i s e e se scan, wo ca hodic peaks a e eco ded a 0.8
V and 0.7 V. The o me is clea ly associa ed wi h he e e sible educ ion o oxidized species
gene a ed du ing he o wa d sweep, whe eas he 0.7 V b oad wa e seems ela ed wi h he
5
educ ion o he oligome p oduc s o med a highe po en ials. Such p oduc s canno be e-
oxidized du ing successi e o wa d sweeps, as mani es ed by he absence o anodic wa es
di e en om ha o monome oxida ion. The peak cu en o he main oxida ion ea u e
dec eases upon cycling and i s ini ially as kine ics decays g adually. The e o e, i is clea ly
deduced om he ol amme ic p o ile ha he anodic oxida ion o aminophenol monome
yields elec ochemically inac i e oligome ic p oduc s ha block he elec ode hinde ing
u he oxida ion. Cyclic ol ammog am in Fig. 1b e eals ha he blocking species a e
s ongly adso bed on pla inum. This cu e was eco ded in a backg ound elec oly e solu ion
a e 300 polyme iza ion cycles, when he su ace appea ed co e ed wi h a pu ple ilm. The
elec ode was emo ed om he polyme iza ion solu ion, washed wi h ul apu e wa e and
ans e ed o he 0.1M HClO4 es solu ion wi h no monome added. The ol amme ic cu e
shows he cha ac e is ic p o ile o a pla inum elec ode co e ed wi h a hin, almos
elec oinac i e oligome ic ilm.
The ea u eless oxida ion p ocess unde gone by poly(2A-4TBP) in Fig. 1b was
moni o ed by in si u UV- is spec oscopy in o de o disce n whe he o no pola onic species
a e o med upon anodic pola iza ion o his ma e ial. The polyme was deposi ed on an ITO
coa ed glass elec ode in a pa allel expe imen o ha shown in Fig. 1a and hen ans e ed o
he spec oelec ochemical cell, whe e i was imme sed a 0.05 V. In si u UV–Vis spec a
we e hen eco ded a inc easing po en ials and hose ob ained in he ange om 0.05 o 0.65
V ha e been depic ed in Fig.2.
The i s UV–Vis spec um collec ed a 0.05 V shows one main abso p ion ea u e a
558 nm. The in ensi y o his peak emains almos cons an a po en ials below 0.45 V bu
ises sha ply abo e ha alue. Such a beha io sugges s a edox ans o ma ion o he
oligome ic ma e ial, wi h he abso p ion p obably associa ed wi h a benzenoid- o-quinoid
ansi ion ela ed o pola onic moie ies o med upon elec ochemical doping [12]. Such a band
is sligh ly blue-shi ed wi h espec o polyaniline and close o he pola onic ansi ions
obse ed o o he ing-subs i u ed polyanilines, indica ing he p esence o pola onic domains
wi h sho conjuga ed segmen s. Howe e , he o ma ion o quinone-like moie ies upon
oligome oxida ion could also con ibu e signi ican ly o his band [13]. The occu ence o a
6
edox pola onic ans o ma ion in poly(2A-4TPB) is also suppo ed by o he spec al ea u es
in Fig 2. Speci ically, he spec um acqui ed a 0.65V shows he appea ance o h ee
addi ional bands cen e ed a 397, 416 and 447 nm. The o me one can be assigned o a
pola on-π* ansi ion, whe e pola ons a e isola ed one om ano he e lec ing low elec ical
conduc i i y o he oligome ic ma e ial [14]. Rega ding he o he wo ea u es i is wo h
men ioning ha , acco ding o li e a u e da a on polyaminophenols, elec onic abso p ions in
he 410-450 nm ange can be a ibu ed o he p og essi e o ma ion o adical ca ions in
phenoxazine ings o , al e na i ely, o he occu ence o N-N coupling o o m azobenzene
de i a i es [15–18]. In he p esen case, bo h s uc u es a e p obably p omo ed by he
p esence o he oluminous e bu yl g oup in me a posi ion ela i e o he ni ogen a om,
which ends o hinde he C-N pa a-coupling and hyd azine- ype dime s could be o med due
o such s e ic hind ance [19]. Finally, he band a 742 nm, whose in ensi y emains almos
cons an a inc easing po en ials, is o unce ain na u e bu i has been assigned ei he o he
bipola onic ansi ion in pa a-coupled polyaniline de i a i es o o he pola on ansi ion in
poly(o-aminophenols) [15,16]. Acco ding o hese esul s, poly(2A-4TBP) seems an
oligome ic p oduc o igina ed om a a ie y o C-N, C-O and N-N monome couplings.
In si u FTIR spec oscopy has been used o con i m he exis ence o a edox ansi ion
in he elec ochemically deposi ed poly(2A-4TBP). The ilmed P elec ode was ans e ed o
he IR spec oelec ochemical cell, which con ained a ee o monome es solu ion p epa ed
wi h D2O o acili a e assignmen s in he 1500-1700 cm-1 spec al ange. A e some po en ial
cycles, he P su ace was ca e ully p essed agains he p isma ic CaF2 window, a e e ence
spec um was hen collec ed a 0.1 V and, inally, he po en ial was s epped o highe alues o
collec sample spec a. By e e ing each sample o he unique e e ence, we can ob ain
in o ma ion on he edox ans o ma ions unde gone by he oligome ic ma e ial as a unc ion
o he applied po en ial. The compu ed in si u FTIR spec a a e displayed in Fig. 3 wi hin he
equency ange 1100-2200 cm-1. The e, he p esence o se e al nega i e (downwa d) and
posi i e (upwa d) bands e eals he ac i a ion o ib a ional modes a inc easing po en ials,
which is a cha ac e is ic beha io o e e sible oxida ion p ocesses.
In ac , since no spec al ea u es appea in he spec a ob ained a 0.3 V and 0.4 V, i
can be in e ed ha poly(2A-4TBP) canno be oxidized a so mode a e po en ials. This
obse a ion is consis en wi h he esul s ob ained om he in si u UV- is expe imen s in Fig.
2. On he con a y, se e al IR abso p ion bands appea in he spec a collec ed om 0.5 V.
7
The onse o oligome oxida ion a a ound his po en ial is es i ied by he occu ence o a
clea nega i e band a 1613 cm-1, a g oup o less in ense nega i e abso p ions in he 1330-
1400 cm-1 equency ange and, inally, wo posi i e bands peaking a 1518 and 1445 cm-1. I
can be obse ed ha he in eg a ed in ensi y o all hese ea u es, and he e o e he oligome
oxida ion le el, inc eases a inc easing po en ials and, besides, new abso p ions showing
ei he nega i e o posi i e cha ac e a e de eloping. Assignmen s p oposed o he main bands
a e summa ized in Table 1. Be ween he wo main bands clea ly ela ed wi h he educed o m
o poly(2A-4TBP), he ea u e appea ing a 1518 cm-1 can be unambiguously assigned o he
p og essi e anishing o he a oma ic C-C s e ching due o oligome oxida ion, whe eas he
peak a 1312 cm-1 is ela ed wi h he pa allel ans o ma ion o seconda y a oma ic amines.
The high in ensi y eached by he o me ea u e is p obably due o he p esence o he
elec on-dono alkyl g oup in he a oma ic ing [20]. The band a 1445 cm-1 has been
some imes a ibu ed o he skele al C-C s e ching ib a ion o he a oma ic ing, al hough he
in e p e a ion o his band is no unanimous. Apa om he C-C s e ching, i has been also
asc ibed ei he o he exis ence o N-N coupling o o he o ma ion o phenazine s uc u es in
polyaniline de i a i es [21,22]. In ou case, owing o he p esence o adjacen alcohol and
amino g oups, i is e y likely he o ma ion o phenoxazine ings and/o N-N coupling. This
hypo hesis seems suppo ed by he in si u UV- is esul s p esen ed in Fig. 2.
Wi h ega d o he oxidized s a e, i is wo h no ing ha he abso p ion bands
appea ing, oughly, below 1600 cm-1 suppo he exis ence o a e e sible edox
ans o ma ion o poly(2A-4TBP). On he con a y, mos ea u es appea ing abo e ha
equency s ongly sugges an i e e sible deg ada ion p ocess o he oligome ic ma e ial a
high po en ials. Indeed, he e e sible o ma ion o quinoid ings and in e media e-o de C≈N
bonds, which is common o mos polyaniline de i a i es, is con i med espec i ely by he
1578 cm-1 ea u e and he g oup o o e lapped bands in he su oundings o 1350 cm-1.
Quinone imine cen e s a e esponsible o he ea u e a 1617 cm-1, while he couple o
nega i e-going bands a 1750 cm-1 and 1292 cm-1 suppo s he o ma ion o ca boxylic acid
e mina ions and con i ms he occu ence o an o e oxida ion p ocess a po en ials beyond
0.9V. Fu he mo e, he nega i e band peaking a 1650 cm-1 e eals he o ma ion o deg aded
quinone s uc u es a 0.9V [3].
14
o poly(o-aminophenol). In addi ion o he e e sible edox ansi ion, he o ma ion o
o e oxidized s uc u es con aining quinone-like s uc u es has been also de ec ed by FTIR,
while UV- is sugges s ha hese s uc u es a e mo e abundan in he elec ochemically
ob ained ma e ial han in he chemical p oduc .
The conduc i i y o poly(2A-4TBP) is lowe han ha o poly(o-aminophenol) and
h ee o de s o magni ude in e io o poly(o- oluidine). Acco ding o his esul , he key ac o
go e ning he poo poly(2A-4TBP) conduc i i y seems he o ma ion o azo g oups (which
can b eak he ex ended conjuga ion) and, p obably, no he e en ual o sion angle be ween
adjacen ings ha elie es he s e ic s ains p omo ed by he e -bu yl g oup. UV- is
ansien species ela ed wi h he polyme main oxida ion peak seem absen in poly(2A-
4TBP), ye hey play a signi ican ole in he elec ical conduc i i y o he pa en poly(o-
aminophenol) polyme .
Acknowledgmen s
Financial suppo om he Spanish Minis e io de Economía y Compe i i idad and
FEDER unds (MAT2013-42007-P) and om he Gene ali a Valenciana
(PROMETEO2013/038) is g a e ully acknowledged. M. Abidi hanks he Minis y o Highe
Educa ion and Scien i ic Resea ch o Tunisia o unding he s ay a he Uni e si y o
Alican e.
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17
0.0 0.2 0.4 0.6 0.8 1.0
-200
0
200
400
600 1s cycle
2nd cycle
5 h cycle
7 h cycle
I / A
E / V s RHE
0.0 0.2 0.4 0.6 0.8 1.0
-20
-15
-10
-5
0
5
10
I / A
E / V s RHE
Fig. 1. a) Cyclic ol ammog ams eco ded o a P elec ode du ing he oxida ion o 15 mM
2A-4TBP in 1 M HClO4. b) Elec ochemical beha io o a poly(2A-4TBP) hin ilm o med
as in Fig. 1a. Tes solu ion: 0.1M HClO4. = 50 mV s-1
18
400 480 560 640 720 800 880
0.00
0.04
0.08
0.12
0.16
Abso bance
Wa eleng h / nm
397 416
558
742
447
Fig. 2. In si u UV– is spec a eco ded o a poly (2A-4TBP) ilm a di e en applied
elec ode po en ials ( om bo om o op: 0.05V, 0.25V, 0.45V, 0.55V, 0.65V). The poly(2A-
4TBP) ilm was p epa ed on ITO coa ed glass om a solu ion con aining 15mM monome in
aqueous 0.1 M HClO4.
19
Fig. 3. Se o in si u FTIR spec a collec ed du ing he oxida ion o an elec ochemically
ob ained poly(2A-4TBP) ilm in 0.1M HClO4/D2O es solu ion. Re e ence po en ial 0.1 V.
Sample po en ial labelled o each spec um. 100 in e e og ams a each po en ial.

20
282 285 288 291
0.0
2.0x104
4.0x104
6.0x104
In ensi y /a.u.
Binding ene gy / eV
C 1s
396 399 402 405 408
0.0
2.0x103
4.0x103
In ensi y /a.u.
Binding ene gy / eV
N 1s
528 531 534 537 540
0.0
5.0x103
1.0x104
1.5x104
2.0x104
In ensi y /a.u.
Binding ene gy / eV
O 1s
Fig.4. High esolu ion XPS signals o C 1s, N 1s and O 1s ob ained om a poly(2A-4TBP)
ilm elec odeposi ed on a pla inum subs a e.
21
0.0 0.2 0.4 0.6 0.8
-100
-50
0
50
I / A
E / V s RHE
Fig.5. Cyclic ol ammog am eco ded in 0.1M HClO4 elec oly e o poly(2A-4TBP)
syn hesized chemically and cas ed on a polyc ys alline pla inum elec ode. = 50 mV s-1.
400 480 560 640 720 800
0.00
0.04
0.08
0.12
0.16
Abso bance
Wa eleng h / nm
385
445
562
739
Fig. 6. In si u UV- is spec a eco ded a di e en elec ode po en ials ( om bo om o op:
0.05V, 0.25V, 0.45V, 0.55V, 0.65V) o a chemically syn hesized poly (2A-4TBP) deposi ed
on ITO. Tes solu ion 0.1M HClO4.
22
Fig. 7. In si u FTIR spec a collec ed du ing he oxida ion o a chemically syn hesized
poly(2A-4TBP) in 0.1M HClO4/D2O es solu ion. Re e ence po en ial 0.1 V. Sample
po en ial labelled o each spec um. 100 in e e og ams a each po en ial.
23
282 285 288 291 294
0
1x104
2x104
3x104
4x104
5x104
In ensi y /a.u.
Binding ene gy / eV
C 1s
393 396 399 402 405 408
0
1x103
2x103
3x103
In ensi y /a.u.
Binding ene gy / eV
N 1s
528 531 534 537 540 543
0.0
5.0x103
1.0x104
1.5x104
In ensi y /a.u.
Binding ene gy / eV
O 1s
Fig. 8. High- esolu ion XPS spec a o chemically syn hesized poly (2A-4TBP) showing he
cu e- i ed signals o C 1s, N 1s and O 1s.