Electrochemical impedance spectroscopy of poly[carbazole-co-N-p-tolylsulfonyl pyrrole] on carbon fiber microelectrodes, equivalent circuits for modelling

Abstract

Polycarbazole (PCz) and copolymerization of carbazole (Cz) and N-p-tolylsulfonyl pyrrole (pTsp), P(Cz-co-pTsp), thin films have been cyclovoltammetrically coated onto carbon fiber electrodes as an active functionalized microelectrode in sodium perchlorate (NaClO4)/acetonitrile (ACN) medium. The resulting thin films of homopolymer and copolymer were characterised by using Fourier transform infrared reflectance spectroscopy (ATR-FTIR), energy dispersive X-ray (EDX) point analysis, scanning electron microscopy (SEM) and atomic force microscopy (AFM). An electrical impedance study on the prepared electrodes is reported in the present paper under different feed ratios of [pTsp](0)/[Cz](0) during electrochemical impedance spectroscopic (EIS) measurements. Specific capacitance (C,,,) were calculated, P(Cz-co-pTsp) in feed ratio of [pTsp](0)/[Cz](0) = 200 has preserved more capacitive behavior especially at lower frequency (C-sp = similar to 156 mF g(-1)) than polycarbazole (C-sp = similar to 2.1 mF g(-1). The electrochemical impedance data fitted to three different equivalent models were used to find Out numerical values of the proposed components. (C) 2008 Elsevier B.V. All rights reserved.