ESR study of polyaniline doping at various concentrations of anions

ESR spectroscopy coupled with cyclic voltammetry was applied to investigate the influence of the doping anion concentration on paramagnetic properties of polyaniline. After the electrochemical synthesis in acid media, in situ ESR measurements were carried out during voltammetric cycling of polyaniline in aqueous solutions containing tungstosilicic acid and various amounts of HCl orHClO4. Changes in paramagnetic properties of polyaniline depend on the concentration of doping anions. ESR spectra and spin density-potential relationships suggest that the anion concentration is an important factor that has a considerable influence on the formation of positive charges in the polymer chain.