Pristine and Overoxidized Polypyrrole by XPS

An x-ray photoelectron spectroscopy (XPS) analysis was performed of polypyrroles (PPy) electrosynthesized on Pt in aqueous solution. Spectra were recorded both for the as-synthesized (pristine) polymer (specimen 1) and for the so-called “overoxidized” PPy (specimen 2). Electrosynthesis was accomplished potentiostatically at +0.7 V vs SCE in KCl 10 mM containing pyrrole 0.4 M. Overoxidized PPy was obtained by keeping the pristine polymer at the electrosynthesis potential for 5 h, in phosphate buffer solution (pH 7). C, N, O (1s), and Cl 2p (pristine) spectra are included. Some minor elements, P (in the overoxidized polymer), Na (in some overoxidized samples), and Si (in other samples of both types of PPy, but not in those here reported), were also detected.