Characterization of the redox processes in polyaniline using capacitance–potential curves

A systematic investigation of the redox properties of polyaniline in aqueous solutions using the capacitance–potential curves was done. The variation of the capacitance values in different regions of the sweep potentials was associated with the charge transport and the capacitive processes in the polymeric film. An increase in the capacitance was observed in the region of the first redox process (0.1 to 0.6 V), which is associated with the charge accumulation in the film due to the polymer oxidation and the Cl− intercalation. In the third redox process in the voltammograms (0.85 to 1.2 V), a decrease in capacitance was observed which could be related to the H+ deintercalation and the formation of the pernigraniline state.