PMID- 20625574
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20101203
LR  - 20100827
IS  - 1463-9084 (Electronic)
IS  - 1463-9076 (Linking)
VI  - 12
IP  - 35
DP  - 2010 Sep 21
TI  - Spectroscopic evidence for intermediate species formed during aniline 
      polymerization and polyaniline degradation.
PG  - 10584-93
LID - 10.1039/c002920c [doi]
AB  - Spectroscopic methods are used to investigate the formation of low molecular mass 
      intermediates during aniline (ANI) oxidation and polyaniline (PANI) degradation. 
      Studying ANI anodic oxidation by in situ Fourier transform infrared spectroscopy 
      (FTIRS) it is possible to obtain, for the first time, spectroscopic evidence for 
      ANI dimers produced by head-to-tail (4-aminodiphenylamine, 4ADA) and tail-to-tail 
      (benzidine, BZ) coupling of ANI cation radicals. The 4ADA dimer is adsorbed on 
      the electrode surface during polymerization, as proved by cyclic voltammetry of 
      thin PANI films and its infrared spectrum. This method also allows, with the help 
      of computational simulations, to assign characteristic vibration frequencies for 
      the different oxidation states of PANI. The presence of 4ADA retained inside thin 
      polymer layers is established too. On the other hand, FTIRS demonstrates that the 
      electrochemically promoted degradation of PANI renders p-benzoquinone as its main 
      product. This compound, retained inside the film, is apparent in the cyclic 
      voltammogram in the same potential region previously observed for 4ADA dimer. 
      Therefore, applying in situ FTIRS is possible to distinguish between different 
      chemical species (4ADA or p-benzoquinone) which give rise to voltammetric peaks 
      in the same potential region. Indophenol and CO(2) are also detected by FTIRS 
      during ANI oxidation and polymer degradation. The formation of CO(2) during 
      degradation is confirmed by differential electrochemical mass spectroscopy. To 
      the best of our knowledge, this is the first evidence of the oxidation of a 
      conducting polymer to CO(2) by electrochemical means. The relevance of the 
      production of different intermediate species towards PANI fabrication and 
      applications is discussed.
FAU - Planes, G A
AU  - Planes GA
AD  - Dpto. de Quimica Fisica, Universidad de la Laguna, 38071-Tenerife, Spain.
FAU - Rodriguez, J L
AU  - Rodriguez JL
FAU - Miras, M C
AU  - Miras MC
FAU - Garcia, G
AU  - Garcia G
FAU - Pastor, E
AU  - Pastor E
FAU - Barbero, C A
AU  - Barbero CA
LA  - eng
PT  - Journal Article
DEP - 20100712
PL  - England
TA  - Phys Chem Chem Phys
JT  - Physical chemistry chemical physics : PCCP
JID - 100888160
EDAT- 2010/07/14 06:00
MHDA- 2010/07/14 06:01
CRDT- 2010/07/14 06:00
PHST- 2010/07/14 06:00 [entrez]
PHST- 2010/07/14 06:00 [pubmed]
PHST- 2010/07/14 06:01 [medline]
AID - 10.1039/c002920c [doi]
PST - ppublish
SO  - Phys Chem Chem Phys. 2010 Sep 21;12(35):10584-93. doi: 10.1039/c002920c. Epub 
      2010 Jul 12.