Electrochemical preparation and study of transport properties of polypyrrole doped with unsaturated organic sulfonates

Electrochemical synthesis of polypyrrole films containing vinyl sulphonate and styrene sulphonate dopants were carried out in a three-electrode one-compartment cell employing galvanostatic conditions at constant charge density. Various parameters like current density, dopant concentration, pH and temperature during synthesis were varied for both the dopant anions. Room temperature conductivity for each sample was measured and their surface morphologies were analysed from the scanning electron microscope pictures. Dependence of conductivity and surface morphology on different synthetic conditions were discussed and probable reasons for the dependence were indicated. For each of the dopant anions, resistivities were measured down to 25 K for samples synthesized at 0 degrees C and room temperature. From the resistivity data, charge transport behaviour in these films were analysed in the light of Mott's variable range hopping model. Ageing effects of conductivity for films containing both the dopant anions were studied by storing them in ambient atmosphere and measuring their conductivities from time to time. Copyright (C) 1996 Elsevier Science Ltd.