Redox behavior and stability of polypyrrole film in sulfuric acid

Acid concentration can profoundly affect the redox behavior and stability of polypyrrole film in sulfuric acid solution. The electrochemical characteristics during the redox process of polypyrrole films prepared with p-toluenesulfonate were investigated by cyclic voltammetry. The redox stability was studied by recurrent potential pulses experiments in different concentrations of sulfuric acid. The reduction charge value (Q(red)), the ratio of the reduction and oxidation charges (Q(red)/Q(ox)) were calculated from the experiments to exclude the polypyrrole films' redox stability with the time and the reversibility of the reduction/oxidation process. FT-IR and SEM were used to study the structure and morphology change of ppy films treated by different concentrated sulfuric acid solutions, respectively. (c) 2006 Elsevier B.V. All rights reserved.