Factors Affecting the Electrochemical Responses of Metal Complexes at Pyrolytic Graphite Electrodes Coated with Films of Poly(4‐Vinylpyridine)

Abstract

Electrochemical responses from the reduction of Ru m (edta) coordinated to films of high molecular weight poly (4-vinylpyridine ) on pyrolytic graphite electrodes were studied as functions of film thickness, temperature, supporting electrolyte composition, and solvent. Responses at filmed electrodes from metal complexes that do not coordinate to the films were also examined. With films thicker than ca. 1000A, the current responses are limited by the rates of molec- ular motions within the films. Penetration of counterions, segmental motion of sections of the polymer chains, and juxtapositioning of pairs of attached metal complexes to facilitate intercomplex electron transfer within the film or com- binations of the three are suggested as likely current limiting processes.