The chemical nature of the nitrogens in polypyrrole and polyaniline: A comparative study by x-ray photoelectron spectroscopy

The chemical nature of the nitrogens corresponding to various intrinsic redox states of polypyrrole (PPY) and polyaniline (PAN) has been critically compared using x-ray photoelectron spectroscopy (XPS) as a primary tool. Proton modifications of nitrogens in PPY give rise to a number of intrinsic redox states analogous to those observed in PAN. The behavior of the corresponding oxidation states in both polymers towards oxidation/reduction, deprotonation/reprotonation, or charge–transfer interactions with electron acceptors are grossly similar. However, the nitrogens of the two oxidized polymer complexes do differ in their thermal degradation behavior which suggests that the oxidized pyrrolylium nitrogens are more susceptible to deprotonation than their oxidized counterparts.