Studies on electrochemical, optical and electrical conductivity of terpolymer of poly[aniline-co-(o-anisidine)-co-(o-toluidine)] using various organic salts

Abstract

An attempt has been made to prepare poly[aniline-co-(o-anisidine)-co-(o-toluidine)] (PAco-POA-co-POT) thin films doped by several organic salts with varying size of cation, using aqueous solution of H2SO4 as electrolyte. The effect of dopant in presence of electrolyte is rarely studied in the field of conducting polymers. Various organic salts as dopants, viz. potassium acetate, sodium acetate and magnesium acetate, were used at room temperature. The films were electropolymerized in solution containing 0.1 M monomer(s), 1 M H2SO4 as electrolyte and 1 M organic salt by applying sequential linear potential scan rate 50 mV/s between –0.2 and 1.0 V versus Ag/AgCl electrode. The electro-synthesized films were characterized by cyclic voltammetry, UV-visible spectroscopy and conductivity measurements. It was observed that the UV-visible peaks appeared at about 816 nm with a shoulder at 420 nm for emeraldine salt (ES) phase of PA-co-POA-co-POT without any doping salt. In the presence of salts, a shift for these absorption spectra is observed to lower wavelength, between 785 and 800 nm; however, a shift of shoulder to higher wavelength at 435 nm was also found. Overall, an increase in conductivity was observed for all dopants mentioned above and amongst these potassium acetate was found to be the best.