Electrochemical behaviour of polyaniline in weak acid solutions

The electrochemical behaviour of polyaniline (PAn) in weak acid solutions such as pH 4 has been studied. It has been found that PAn gives a stable redox reaction involving electrolyte anions in a limited potential region, whereas it loses its electrochemical activity by being oxidized at more anodic potentials where deprotonation preferentially takes place. Detailed mechanisms of the redox and the inactivation reaction of PAn in weak acid solutions are discussed.