Electrochemical response of poly(o-ethoxyaniline) films produced by different techniques

Poly(o-ethoxyanilines) (POEA) were synthesized electrochemically and chemically in aqueous acid media. POEA films were readily obtained during the electrochemical deposition on platinum electrodes, while the chemically synthesized material was processed in the form of films either by drop coating or by Langmuir-Blodgett (LB) deposition. The open circuit potential values measured during the chemical synthesis, as well as the color changes observed, are in close agreement with those of the electro-polymerization indicating basically the same changes in oxidation states of the polymer structures. The electrochemical response of all films was investigated by cyclic voltammetry. Two redox processes were observed after stabilization in the electrolyte solution, which are associated with interconversion reactions involving different oxidation and protonation states. Ultra-thin LB films required the shortest time for stabilization. POEA films displayed electrochromism, with color changes from yellow to violet as a function of the potential.