Raman spectrum, consistent with a decrease of the absorbance
at 1064 nm (see Fig. 3). Evidently, at this potential, none of the
polymer segments are in resonance with the infrared excitation
line. Upon oxidation of this totally reduced form of P4, the
spectrum reappears at E = +0.10 V giving lines characteristic
of the protonated semi-oxidized form of the oligoaniline side
groups. At E = +0.20 V the spectrum is identical to that
registered at the open circuit potential proving that in the
acidified electrolyte the redox processes in the potential range
of the first redox couple are reversible, at least in the chemical
sense. This is not unexpected since the semioxidized, proto-
nated form of the aniline tetramer has, in its cationic part,
the same stoichiometry as the fully reduced form. As a
consequence the switching between these forms involves only
the electron transfer.
protonation–deprotonation phenomena occurring in acidified
electrolytes.
Acknowledgements
Some of the authors (K.B., A.M., R.P., M.Z.) acknowledge
financial support by Warsaw University of Technology.
References
1 R. D. McCullough, Adv. Mater., 1998, 10, 93.
2 M. Besbes, G. Trippe´, E. Levillain, M. Mazari, F. Le Derf,
I. F. Perepichka, A. Derdour, A. Gorgues, M. Salle´ and J. Roncali,
Adv. Mater., 2001, 13, 1249 and references therein.
3 J. Lowe and S. Holdcroft, Macromolecules, 1995, 28, 4608.
4 N. Miyaura, Topics in Current Chemistry: Cross-Coupling
Reactions, Vol. 219, Springer, Berlin, 2002.
In the potential range of +0.10 V , E , +0.50 V the lines
characteristic of the protonated semi-oxidized form of the
tetramer side group grow in intensity as a result of improving
resonance conditions for this form. Evidently the continuous
increase of the absorbance at 1064 nm, registered for increas-
ing electrode potentials is caused, in this case, by growing
content of the protonated side-group tetramer. Above E =
+0.50 V the resonance conditions worsen and the intensity of
the observed Raman lines diminishes. It should be stressed
that the lines originating from the polythiophene main chain
remain ‘‘invisible’’ for the Raman spectroscopy throughout
the whole potential range studied. At the highest potentials
spectra of a very poor quality, with no distinguishable
Raman lines, are registered. This can be considered as a
spectroscopic manifestation of the polymer degradation.
Evidently, for potentials exceeding the maximum of the second
anodic peak the oxidative degradation of P4 is accelerated in
acidified electrolytes.
5 Y. Li, G. Vamvounis and S. Holdcroft, Macromolecules, 2002, 35,
6900.
6 M. Lanzi, L. Paganin, P. Costa-Bizzarri, C. Della-Casa and
A. Fraleoni, Macromol. Rapid Commun., 2002, 23, 630.
7 M. Lanzi, L. Paganin and P. Costa-Bizzarri, Eur. Polym. J., 2004,
40, 2117.
8 G. Trippe´, F. Le Derf, J. Lyskawa, M. Mazari, J. Roncali,
A. Gorgues, E. Levillain and M. Salle´, Chem. Eur. J., 2004, 10,
6497.
9 P. Ba¨uerle, M. Hiller, S. Scheib, M. Sokolowski and E. Umbach,
Adv. Mater., 1996, 8, 214.
10 A. Iraqi, J. A. Crayston and J. C. Walton, J. Mater. Chem., 1998,
8, 31.
11 G. Li, G. Koßmehl, W. Hunnius, H. Zhu, W. Kautek, W. Plietch,
J. Melsheimer and K. Doblhofer, Polymer, 2000, 41, 423.
12 L. Zhai, R. L. Pilston, K. L. Zaiger, K. K. Stokes and
R. D. McCullough, Macromolecules, 2003, 36, 61.
13 G. Zotti, S. Zecchin, G. Schiavon, B. Vercelli and A. Berlin,
Electrochim. Acta, 2005, 50, 1469.
14 B. Dufour, P. Rannou, J. P. Travers, A. Pron, M Zagorska,
G. Korc, I. Kulszewicz-Bajer, S. Quillard and S. Lefrant,
Macromolecules, 2002, 35, 6112.
´
15 K. Buga, K. Ke˛pczynska, I. Kulszewicz-Bajer, M. Zago´rska,
At the end, it should be stressed that all three (UV–vis, EPR
and Raman) spectroelectrochemical techniques together with
cyclic voltammetry give a very clear and consistent response
concerning the electrochemical oxidative doping of the
precursor polymer P1 and its oligoaniline functionalized
derivatives (P3 and P4).
R. Demadrille, A. Pron, S. Quillard and S. Lefrant, Macro-
molecules, 2004, 37, 769.
16 K. Buga, A. Majkowska, R. Pokrop, M. Zago´rska, D. Djurado,
A. Pron, J.-L. Oddou and S. Lefrant, Chem. Mater., 2005, 17,
5754.
17 R. Demadrille, B. Divisia-Blohorn, M. Zagorska, S. Quillard,
S. Lefrant and A. Pron, Electrochim. Acta, 2005, 50, 1597.
18 D. K. Grant and D. L. Officer, Synth. Met., 2005, 154, 93.
19 S. Gambihr, K. Wagner and D. Officer, Synth. Met., 2005, 154,
117.
Conclusions
20 P. Costa-Bizzarri, F. Andreani, C. Della Casa, M. Lanzi and
E. Salatelli, Synth. Met., 1995, 75, 141.
21 B.-S. Kim, L. Chen, J. Gong and Y. Osada, Macromolecules, 1999,
32, 3964.
22 B. Neises and W. Steglich, Angew. Chem., Int. Ed. Engl., 1978, 17,
522.
23 T. Kirschbaum, R. Azumi, E. Mena-Osteritz and P. Bauerle, New
J. Chem., 1999, 23, 241.
24 J. Pei, J. Ni, X.-H. Zhou, X.-Y. Cao and Y.-H. Lai, J. Org. Chem.,
2002, 67, 4924.
25 N. Miyaura and A. Suzuki, Chem. Rev., 1995, 95, 2457.
26 S. Gronowitz and D. Peters, Hetercycles, 1990, 30, 645.
27 G. E. Collis, A. K. Burrell, S. M. Scott and D. L. Officer, J. Org.
Chem., 2003, 68, 8974.
28 R. Demadrille, P. Rannou, J. Bleuse, J. L. Oddou, A. Pron and
M. Zagorska, Macromolecules, 2003, 36, 7045.
29 J. S. Liu and R. D. McCullough, Macromolecules, 2002, 35, 9882.
30 P. Barta, P. Dannetun, S. Stafstrom, M. Zagorska and A. Pron,
J. Chem. Phys., 1994, 100, 1731.
31 R. P. McCall, J. M. Ginder, J. M. Leng, H. J. Ye, S. K. Manohar,
J. G. Masters, G. E. Asturias, A. G. MacDiarmid and A. J. Epstein,
Phys. Rev. B: Condens. Matter, 1990, 41, 5202.
To summarize, we have developed an efficient method of the
preparation of alternate copolymers of dialkylbithiophenes
and oligoanilinethiophenes in which the thiophene rings are
head to head coupled. These solution processable polymers
show very interesting electrochemical behaviour associated
with two types of electroactive groups (side and main chains).
In particular, their electrochemical doping is sequential
which means that at lower electrode potentials they can be
selectively doped in their oligoaniline side chains whereas at
higher potentials the doping is global i.e. involves both the
side chains and the polythienylene main chain. This conclusion
is drawn from a careful analysis of a consistent evolution of
UV–vis, Raman and EPR spectra registered for increasing
electrode potentials and from the correlation of these
changes with the observed voltammetric features. Spectro-
electrochemical investigations show additionally that the redox
processes in the electroactive side chains are facilitated by
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