STUDIES ON REACTIONS PROCEEDING AT THE INTERFACE BETWEEN CONDUCTING POLYMER AND REDOX ELECTROLYTE

The kinetics and mechanism of electrochemical reactions of cationic Fe3+/Fe2+ and anionic Fe(CN)63-/Fe(CN)64- redox couples were studied at glassy carbon (GC) electrodes covered (i) by poly-N-methylpyrrole (PMPy) with perchlorate mobile counter-anions and (ii) by poly-N-methylpyrrole with immobilized poly-4-styrenesulfonate anions (PMPy/PSS) exhibiting properties of a cation exchange membrane. The results obtained are analyzed on the basis of a model, in which the charge transfer is regarded as a chemical redox reaction between electroactive species in solution and the oxidized or reduced sites of the conducting polymer. The influence of Donnan potential on kinetics of such charge transfer reactions is demonstrated.