On the time scale of the structural change of polyaniline in the reversible electrochemical process

The conducting polymer system is presented for the first time that exhibits the usual quasi-reversibility under the very slow cyclic voltammetry conditions. The hysteresis in the cyclic voltammograms of the secondary trichloroacetate counterion-polyaniline system decreases with a decrease of scan rate. The behavior is not observed for the primary chloride counterion-polyaniline system. The low frequency impedance spectroscopy results are invoked to discuss the observed phenomenon. The time scale of the polymer structural rearrangement due to the reversible electrochemical oxidation process is estimated to be at least of the order of 10(3) s. A specific molecular interactions are postulated to interpret the difference observed between the secondary and primary counterion systems. (C) 1998 Elsevier Science S.A. All rights reserved.