Studies on electrochemical, optical and electrical conductivity of o-anisidine, o-toluidine and their co-polymer using various organic salts

Abstract

An attempt has been made to prepare poly((o-anisidine)-co-(o-toluidine)) (POA-co-POT) thin films doped by several organic salts with varying size of the cation, using an aqueous solution of H2SO4 as electrolyte. 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 electro-polymerized 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-Vis spectroscopy and conductivity measurements. It was observed that the UV-Vis peaks are appearing at about 802–816 nm with a shoulder at 410–426 nm for emeraldine salt (ES) phase of POA, POT and POA-co-POT without any doping salt. In the presence of salts, a shift for these absorption spectra is observed to lower wavelength, in between 758–810 nm; however, the shoulder is shifted to a higher wavelength, i.e., 413–435 nm. Overall an increase in conductivity was observed for all above-mentioned dopants and amongst these potassium acetate was found to be the best.