Plasma treatment of polyaniline films: Effect on the intrinsic oxidation states

Abstract

Surface modification of emeraldine (EM) and nigraniline (NA) base films by argon plasma treatment was investigated by x-ray photoelectron spectroscopy (XPS). Argon plasma treatment, followed by atmospheric exposure, results in the oxidation of some carbon atoms, first to C-O species and then to C = O and COOH species for samples with extended plasma treatment time. Most important of all, Ar plasma treatment and the accompanied carbon oxidation readily cause a decrease in the intrinsic oxidation state ([= N-]/[-NH-] ratio) of the aniline polymers.