Electrochemistry of conducting polypyrrole films

Abstract

Polypyrrole, poly-N-methylpyrrole and poly-N-phenylpyrrole polymers are prepared by the electropolymerization of the corresponding pyrrole monomer. Films of these polymers on platinum when mounted in a acetonitrile/Et4NBF4 solution can be electrochemically driven between the oxidized (conducting) form and the neutral (insulating) form. The measured E0 values are equal to -220, +480 and +600 mV vs. SSCE for polypyrrole, poly-N-methylpyrrole and poly-N-phenylpyrrole, respectively. The films are stable to this reaction and can be cycled repeatedly without evidence of decomposition. The cyclic voltammograms show that the reactions are not electrochemically reversible and the kinetic limitations of the reactions depend on the nature of the electrolyte salt. This reaction involves the oxidation of the extended π-system of the polymers and produces a color change in the film from yellow when neutral to black when oxidized. © 1981 Elsevier Sequoia S.A.