In situ potential dependence of poly(aniline) paramagnetism.

Combination of electron-spin resonance and electrochemical voltammetric measurements reveals a behavior, unique among known conducting polymers, for thin, electrochemically deposited films of poly(aniline). ESR absorption is strongly potential dependent. Quantitatively, the number of unpaired spins closely correlates with charge injected during electrochemical oxidation and reduction. The potential dependence, with narrow maxima at the 0.2 and 0.8V insulator-conductor transitions, is consistent with the distribution of levels for a one-dimensional band of electronic energies.