Electrochemical Behavior of Polythiophene Films: Effect of Electrolyte Concentration and the Nature of the Alkyl Substituent

The electrochemical behavior of poly(3-methylthiophene) and poly(3-octylthiophene) films in solutions of 0.05–0.5 M LiClO₄ in acetonitrile is studied using cyclic voltammetry and chronoamperometry. An analysis of data on the current relaxation following a film perturbation by a pulsed small voltage reveals the presence of two constituents of the current relaxation for either polymer, each constituent exponentially depending on the time. Effect of the electrode potential and electrolyte concentration on the current relaxation parameters are studied. Results of additional studies of poly(3-methylthiophene) films by a faradaic impedance method conform to the chronoamperometry data and permit a more reliable interpretation of them.