Anodic overoxidation of polypyrrole in the presence of nucleophiles such as H2O, OH−, CH3OH, CH3O−, Br− and CN− has been studied in detail. At potentials up to 2.1 V (vs. SCE), irreversible anodic peaks are observed with 200 nm layers on Pt. In most of the cases, a total of z = 4 – 6 F/mol monomer unit initially oxidized in the reversible potential region to the radical cation has been evaluated. Only every third ring is involved by this way. Characteristic products in aqueous systems are pyrrolinones (with a keto group in 3‐position), z = 4, and the product of further hydroxylation in 4‐position (z = 6). In the presence of the other nucleophiles, corresponding substitution products seem to be generated. The central reactive intermediate seems to be the dication. Pronounced deviations from this scheme, which is confirmed by IRRAS results, seem to proceed in the presence of strong nucleophiles as OH−, which add initially to the radical cation, and upon strong polarization, which may lead to an attack of the other rings and/or polymer destruction. Practical implications are due to polymer modification and battery material optimization.

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Polypyrrole has been electrodeposited at a constant current density of 4 mA cm−2 onto Pt from 0.1 M pyrrole, 0.1 M NBu4 BF4 in dry CH3CN. The thickness of the polypyrrole has been varied over a wide range of 0.02 to 50 μm. Elemental analysis reveals an excess of hydrogen in the polymer. The electrochemical equivalent corresponds to an insertion of 25–35 mole % BF4‐anions and a current efficiency of 80–100% for the electrodeposition process. SEM technique shows a highly textured material at a thickness larger than 1 μm. Reversible water vapour adsorption of this material has been detected. The potential/time curve during galvanostatic electrodeposition is without special features. The start potential, USSCE = 0.9 V, is relatively negative. A slight decay of potential in the course of the electrodeposition of thick layers is explained in terms of increasing surface roughness. Cyclic voltammetry has been used for a systematic investigation into the role of the positive and negative endpotentials. The importance of a total primary discharge after electrodeposition has been clarified. At a film thickness d exceeding 1 μm, the cyclovoltammetric curve degenerates, and the anodic peak flattens and shifts to more positive potentials. Active mass utilization decreases with increasing d and with increasing voltage scan rate vs. The plot of anodic peak current density vs. vs is linear for layers below 1 μm thickness. For thick layers and at high vs, deviations occur, indicating a transport limitation in the film. As the film is not homogeneous, a quantitative evaluation is not possible.

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