Ultra-fast electropolymerization of pyrrole in aqueous media on oxidizable metals in a one-step process

Abstract

A general one-step electrosynthesis process for polypyrrole (Ppy) films applicable to a large range of oxidizable metals is described. The process is based on the use of an aqueous medium containing a salicylate salt and pyrrole. The salicylate salt is quite specific: it passivates the substrate without preventing electropolymerization of pyrrole and, therefore, makes it possible to obtain strongly adherent PPy films, with controlled thickness, either by cyclic voltammetry or by electrolysis at constant current. In the latter case the process does not involve any induction period corresponding to a preliminary dissolution of the metal, the current efficiencies are close to 100%, and the deposition rate can be very high (1 μm s −1 , corresponding to current densities as high as 500 mA cm −2 ).