STUDY OF OVEROXIDIZED POLYPYRROLE USING X-RAY PHOTOELECTRON-SPECTROSCOPY

Overoxidation of polypyrrole was carried out electrochemically and stu died by X-ray photoelectron spectroscopy. It is shown that overoxidati on starts on the polymer adjacent to the electrode and then advances t o the polymer facing solution. During overoxidation, original positive charges on polypyrrole (-NH+-) are mostly replaced by -NH-, accompani ed by the loss of counterions. Overoxidation progresses in two steps. Carbons are oxidized into C OH in the first step and into C=O in the s econd step. Changing the pH of the media and increasing the potential have no significant effects on the degree of overoxidation in the rang e studied.