Polymer, Vol.35, No.3, 504-508, 1994
Study of Overoxidized Polypyrrole Using X-Ray Photoelectron-Spectroscopy
Overoxidation of polypyrrole was carried out electrochemically and studied by X-ray photoelectron spectroscopy. It is shown that overoxidation starts on the polymer adjacent to the electrode and then advances to the polymer facing solution. During overoxidation, original positive charges on polypyrrole (-NH+-) are mostly replaced by -NH-, accompanied 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 second step. Changing the pH of the media and increasing the potential have no significant effects on the degree of overoxidation in the range studied.