Synthesis and Characterization of a Polyaniline-Polyvinyl Alcohol (PANI-PVA) Composite As Anion-Exchange Membrane

Abstract

Different polyaniline-polyanilylalcohol composites with different concentrations of constituent polymers and degrees of cross-linking were synthesized by chemical oxidative polymerization of aniline in an acidic medium. The electrochemical properties of the PANI/PVA composites were evaluated by electrochemical impedance spectroscopy (EIS), cell diffusion and sorption experiments. The following resistivity, permselectivity, permeability, ion exchange capacity, and chemical stability properties, were obtained and were used to estimate the diffusion coefficients across the membrane for Na+, Cl- and OH- ions. The PANI/PVA composites exhibited high conductivities, especially for higher PANI compositions, given the electrical properties of PANI. Also, although the degree of crosslinking provides higher resistance, it reduces the electrical properties of the membrane, also decreasing the mobility of ions passing through the membrane. Based on the results, potential applications of PANI/PVA in alkaline fuel cells and reverse electrodialysis technology are discussed. PANI base blends and composites have been widely reported due to their low cost and easy preparation through chemical and electrochemical routes. The properties and performance of the composite materials were compared with commercial and custom-made membranes.