Hideharu Daifuku

A study of the redox reaction mechanisms of polyaniline using a quartz crystal microbalance

Etude des reactions redox de films de polyaniline en milieu non-aqueux (LiClO 4 /acetonitrile). Le mecanisme redox est different de celui observe en milieu aqueux

Quartz crystal microbalance study on redox reaction mechanism of polyaniline

Abstract Redox reaction mechanism of polyaniline (PAni) has been investigated in aqueous and non-aqueous electrolyte solutions by electrochemical quartz crystal microbalance (QCM). It was observed that the redox behavior of PAni in non-aqueous system was distinct from that in aqueous system especially in the second (more positive) peak of the cyclic voltammogram. In acidic aqueous solution, it was suggested that there may exist deprotonation of nitrogen atoms in the polymer chain with release of dopant anions at the second oxidation peak. In non-aqueous solution, it was suggested that the second oxidation process as well as the first must be accompanied by anion insertion (so-called anion doping). Accoding to these findings, a possible reaction scheme of PAni in non-aqueous system has been proposed. In addition, it was observed that PAni could be oxidized to the doping level of ca. 0.8 electron per aniline unit in LiCLO4/propyrene carbonate, which is consistent with the reaction scheme proposed.