Electrochemical synthesis and properties of polycarbazole films in protic acid media.

Conductive films are deposited onto Au by anodic oxidation of carbazole dissolved in aqueous alcoholic HClO4. Cyclic voltammetry of film electrodes in aqueous HClO4 prepared in this way shows the occurrence of two main redox processes: an intermediate system becoming less important on cycling is ascribed to dimers or trimers. The polymer is remarkably stable when cycling involves only the first peak, while the second oxidation leads to degradation. An acid environment appears to be essential for film electrochemistry: ESR data confirm that protonation ensures conductivity of the material. On this basis, structure and conduction mechanisms similar to those of emeraldine are suggested.