Electrochemical synthesis of polypyrrole at a novel ‘self-doped’ polyaniline modified electrode

Conducting polymers have received much attention due to their unique physical and chemical properties. Polyaniline, polypyrrole and polythiophene are the most studied conductive polymers [1]. In the present research, a new approach is described for electrosynthesis of polypyrrole (PPy) on a polyelecrtrolyte modified electrode. The electrode was modified by water soluble conducting polymer, poly(2-methoxy aniline -5- sulfonic acid) (PMAS). Modified electrode was prepared by direct drop casting of 10 microliters of a PMAS solution (0.1-5%, w/v) on a glassy carbon electrode. The electrodeposition of the polypyrrole material is enhanced by the presence of the electrically conducting PMAS polyelectrolyte dopant, which functions as a molecular template providing supramolecular pre-ordering as well as simultaneously facilitating charge transport during electrodeposition. Electrochemical experiments showed that even at very low concentrations of pyrrole monomer (0.025 M), an adherent, uniform and stable polypyrrole film is deposited on electrode surface. Post synthesis cyclic voltamograms of polypyrrole showed characteristic redox pairs of electroactive polypyrrole. The method has the advantage of minimizing the amount of PMAS and monomer for deposition of a desirable conducting polymer film.