Coating of gold substrates with polyaniline through electrografting of aryl diazonium salts

The results of an experimental study on electrochemical preparation of polyaniline (PANI)/polycrystalline gold composites are reported in this work. A three steps approach is adopted in order to obtain a stable and uniform coating: (1) functionalization of the gold surface by 4-nitrophenyl group, (2) electrochemical reduction of the nitro group to amine, and (3) electropolymerization of aniline onto the surface of the aminophenyl-modified gold electrode. Cyclic voltammetries and electrochemical impedance spectroscopies are used to characterize the gold surface after each step. Also the results of a sample prepared by electropolymerization of PANI on bare gold are presented as a comparison.