Electrodes coated with conducting polypyrrole film were studied in aqueous solns. by in-situ ESR-electrochem. measurements. It was qual. shown that the spin concentration is directly dependant on the oxidation state of polypyrrole. In transient processes, the formation of spins and their transformation to spinless structures were correlated with electrochem. charge injections. The experimental results are explained in terms of polaron and bipolaron formations in the electrochem. redox processes. ESR-electrochem. behaviors of the polymer-coated electrodes in solns. containing ascorbic acid were also investigated. The charge transfers in polypyrrole film might include contributions from both polarons and bipolarons.

Key words: OXIDATION, MEMBRANE ELECTRODES, ELECTROLYTE, REDUCTION REACTION, ELECTRON SPIN RESONANCE, ELECTRICAL CONDUCTIVITY, CHARGE TRANSFER, POLYMER FILMS, POLYPYRROLE, POLARIZATION FACTOR