Preparation of polypyrrole silica glass composite films by sol-gel process and their electrochemical properties

Polypyrrole (PPy)-silica glass composite films were prepared by carrying out the electrochemical polymerization of PPy simultaneously with the synthesis of silica glass via a sol-gel process, and its electrochemical doping properties were investigated by cyclic voltammetry. These films could be easily doped electrochemically; the undoped and doped states were yellow and blue, respectively. The redox process in PPy-silica glass was gradually activated by repeating the electrochemical doping-undoping cycles. It was found that dopant anions in the PPy-silica glass composite film could be exchanged relatively easily with electrolyte anions in acetonitrile solution by potential sweeping. However, dopant anions in the PPy film could not be easily exchanged in acetonitrile solution. Finally, application of this new type of PPy-silica glass composite film in an ionic sensor which responds to specific ions has also been proposed. (C) 1997 Scripta Technica, Inc.