Synthesis and characterization of poly (aniline-co-o-anisidine-co-o-toluidine) thin films in inorganic and organic supporting electrolytes

Abstract

The influence of inorganic and organic supporting electrolytes on electrochemical, optical and conducting properties of poly(aniline-co-o-anisidine-co-o-toluidine), a terpolymer thin films have been investigated. Homo and terpolymer thin films were synthesized electrochemically, under cyclic voltammetric conditions in aqueous solutions of inorganic acids, viz. H2SO4, HCl, HNO3, H3PO4 and HClO4 and organic acids, viz. benzoic acid, cinnamic acid, oxalic acid, malonic acid, succinic acid and adipic acid at room temperature. The films were characterized by cyclic voltammetry, UV-Visible spectroscopy and conductivity measurements using four probe technique. It was observed that the current densities are strongly influenced by the size and the nature of the anion present in the electrolyte. The optical absorption spectra indicated that the conducting emeraldine salt (ES) phase formed in all the inorganic electrolytes used, whereas it formed only in oxalic acid amongst the organic acids supporting electrolytes. The conductivity of thin films was found to be greatly affected by the nature and size of the anion present in the electrolyte. In case of terpolymer (PA-co-POA-co-POT), the conductivity lies in between the conductivity of the homopolymers PA, POA and POT, irrespective of the supporting electrolyte used. Differential scanning colorimeter (DSC) study also proved the formation of terpolymer.