ELECTROCHEMICAL RESPONSE OF POLY(O-ETHOXYANILINE) FILMS PRODUCED BY DIFFERENT TECHNIQUES

Poly(o-ethoxyanilines) (POEA) were synthesized electrochemically and c hemically in aqueous acid media. POEA films were readily obtained duri ng the electrochemical deposition on platinum electrodes, while the ch emically synthesized material was processed in the form of films eithe r by drop coating or by Langmuir-Blodgett (LB) deposition. The open ci rcuit potential values measured during the chemical synthesis, as well as the color changes observed, are in close agreement with those of t he electropolymerization indicating basically the same changes in oxid ation states of the polymer structures. The electrochemical response o f all films was investigated by cyclic voltammetry. Two redox processe s were observed after stabilization in the electrolyte solution, which are associated with interconversion reactions involving different oxi dation and protonation states. Ultra-thin LB films required the shorte st time for stabilization. POEA films displayed electrochromism, with color changes from yellow to violet as a function of the potential.