Electrochemistry of Conductive Polymers: IV Electrochemical Studies on Polyaniline Degradation — Product Identification and Coulometric Studies

Electrochemical studies on the degradation reactions of oxidized polyaniline (PA) have been carried out to identify major soluble degradation products. As a result of spot tests as well as spectrophotometric experiments, p‐benzoquinone (BQ) was identified as a major degradation product. The overall number of electrons consumed per anilinium unit for the oxidation followed by degradation of PA was determined to be approximately two employing coulometric experiments. The yield for the BQ generation was close to 100% based on this number of electrons transferred. During the later stages of the degradation, the net hydrolysis rate follows first‐order kinetics and is a function of the film thickness. In addition, the hydrolysis reaction is shown to cease upon open circuit of the cell. Finally, a reaction mechanism which accounts for the observed behaviors is proposed.