Electrochemical Synthesis and Characterization of Homo- and Copolymer of Aniline and o-Anisidine in Various Organic Salts

Abstract

An attempt has been made to prepare polyaniline (PA), poly (o-anisidine) (POA), and their copolymer poly (aniline-co-o-anisidine) (PA-co-POA) thin films dopped by several organic salts with varying size of cation, using an aqueous solution of H2SO4 as the electrolyte. The effect of using a dopant in presence of an electrolyte is studied less in the field of conducting polymers. Various organic salts, viz., potassium acetate, sodium acetate, and magnesium acetate were used as dopants 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 the sequential linear potential scan rate 50 mV/s between − 0.2 and 1.0 V vs. Ag/AgCl electrode. The electrosynthesized films were characterized by cyclic voltammetry, UV–Visible spectroscopy, and conductivity measurements. The UV–Visible spectra were obtained ex situ in DMSO and peaks were observed to appear at about 810–826 nm with a shoulder at 416–426 nm for the emeraldine salt (ES) phase of PA, POA, and PA-co-POA without any doping salt. In the presence of salts, a shift for these absorptions was observed to lower wavelength (786–810 nm); however, a shift of shoulder to higher wavelength (424–435 nm) occurred. In the overall study, an increase in conductivity was observed for all aforesaid dopants; among these, potassium acetate was found to be the best.