Studies on electrochemical, optical and electrical conductivity characteristics of copolymer of polyaniline-co-poly(o-toluidine) using various organic salts

摘要

An attempt has been made to prepare polyaniline (PA), poly(o-toluidine) (POT) and their copolymer polyaniline-co-poly(o-toluidine) (PA―POT) thin films doped by several organic salts with varying size of cation, using aqueous solution of H_2SO_4 as electrolyte. Effect of dopant in the presence of electrolyte is rarely studied in the field of conducting polymers. Various organic sails 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 H_2SO_4 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 voltammetiy, UV―Visible spectroscopy and conductivity measurements. The UV―Visible spectra were obtained ex situ in dimethyl sulfoxide (DMSO) and peaks are observed to appear at about 800-810 nm with a shoulder at 410―420 nm are for emeraldine salt (ES) phase of PA, POT, PA―POT without any doping salt. In the presence of salts, a shift for these absorptions was observed to lower wavelength (758―786 nm), however, a shift of shoulder to higher wavelength (413―425 nm). In overall study, an increase in conductivity was observed for all aforesaid dopants and among these, potassium acetate was found to be the best.