Electrochemical properties of chemically and electrochemically synthesized polyniline
Date
1998-11-07
Authors
Chandrakanthi, R. L. N.
Gunaratne, L. M. W. K.
Vidhanapathirana, K.
Careem, M. A.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya
Abstract
Polyaniline(P ANI) is one of the most promising electronically conducting
polymers for technological applications such as rechargeable batteries, electrochromic
displays and sensors. Further, PANI is highly electroactive and it has relatively high
doping levels than the other electronically conducting polymers. Therefore it is a
suitable candidate for cathode materials in plastic batteries.
The PANI system differs from other conducting polymers because of the
presence of more than one redox process and because of the possibility of protonation
of the polymer chain itself, in addition to the negative counterions more loosely doped
to the chain. Therefore, its properties depend on both the pH of the solution it is treated
with and on the oxidation potential. Due to this complexity, the reported results on
PANI in the literature differ considerably. Unlike many other conducting polymers,
PANI can be prepared by chemical or electrochemical synthesis. The work reported in
the literature is mostly confined to systems prepared by one of these methods.
In this study, electrochemical behaviour of PANI films prepared by both
process are reported. Electrochemical synthesis was carried out in 0.1 M aqueous
ethanedisulfonic acid (EDSA) solution. PANI films of 0.25 11m thickness were obtained
galvanostatically at a constant current density of 62.5 IlAlcm2 using the standard two
compartment, three electrode cell arrangement. Films were also prepared by
momentarily dipping a clean platinum wire in solution containing chemically
synthesised PANI in formic acid. Cyclic voltarnetry and in-situ electrical conductivity
variation studies were carried out in aqueous electrolytes containing ethanedisulfonic
acid.
The cyclic voltarnmograms for both type of films have identical features
indicating the films obtained may be the same form. PANI changes from non
conducting state to conducting state on partial oxidization and reverts back to non
conducting state when it is fully oxidized. In the conducting state the electrical
conductivity seemed to vary with applied potential. The conductivity has the highest
value at a potential close to the first anodic peak of the corresponding voltammograme.
Description
Keywords
Electrochemical , Chemically , Synthesized , Polyaniline
Citation
Proceedings & Abstracts of the Annual Research Sessions 1998, University of Peradeniya, Peradeniya, Sri Lanka, pp.116