Electrosynthesis and Properties of Ring-Substituted Polyanilines

Electrochemical polymerization of ring-substituted anilines, with electron donor and acceptor substituents in the 2- and 3-positions, was investigated in 2.0 M sulfuric acid. Polymerization is mostly effective with sigma- and pi-donor substituents, the latter in the 2-position. Polymeric deposits were obtained from 2- and 3-methylaniline (toluidines), 2-methoxyaniline (anisidine) and 2-chloroaniline, and were characterized by cyclic voltammetry, elemental analysis, ir spectroscopy, uv-vis spectroelectrochemistry and electrical conductivity. Polytoluidine and polyanisidine are reversibly oxidized in two steps as polyaniline, whereas polycholoroaniline is oxidized in a single one-electron process. Polymerization was found to be more effective on polyaniline-modified electrodes.