STABILITY AND ELECTROCHEMICAL CHARACTERISTICS OF POLYANILINE SALT FILMS IN 1 N HCL SOLUTION

Thin films of polyaniline (PANI) salts were in situ deposited on a Pt plate during either chemical polymerization or electrochemical polymer ization. The oxidation states of the salt films were controlled by the applied DC potential. AC impedance of the Pt/PANI electrode were meas ured in monomer-free 1 N HCl solution in order to investigate the elec trodic properties of the films at the following applied DC potentials: 0, 0.45 and 0.75 V vs. SCE. Very small differences in film conductivi ty according to its oxidation state were observed by analysis of the i mpedance spectra, the reasons of which are complicated by enriched wat er content in the film and possible decrease in the film thickness dur ing the measurements. The electrochemical activity of the film/solutio n interface varied with its oxidation state. Stability of the film in 1 N HCl solution was also evaluated by impedance and cyclic voltammetr y measurements.