Low potential electropolymerization and copolymerization of diphenylamine on aluminium

The main electrodeposition problem of conducting polymers on oxidizable metals is the higher potential gap between their oxidation and the electropolymerization reaction. This difference provides a dissolution of the electrode before the formation of the polymer. In this context, the present work is aimed to the electrochemical synthesis of polydiphenylamine (PDPA) and its copolymer on aluminium (Al) substrate. The electropolymerization has been performed in two different electrolytic media. We have found that the hydro-organic medium was particularly suitable for carrying out the electropolymerization of DPA on Al at a low potential, 0.6 V, instead of 1 V in the organic medium. Furthermore, the anticorrosive properties of the coatings were studied by linear polarization, open-circuit potential and electrochemical impedance spectroscopy. Finally, the copolymerization of DPA with aniline was investigated in the aim to improve the adherence and the protective performance of the polymeric film.