THE RELEVANCE OF AN EQUIVALENT-CIRCUIT FOR POLYANILINE USING IMMITTANCE SPECTROSCOPY

This paper describes the analysis of electrochemically synthesized polyaniline (PANI) films by immittance spectroscopy. High quality fits to immittance data using a non-linear least-squares fitting routine and the resultant equivalent circuits are described. The circuits are sensitive to changes in the thickness and oxidation state of the films. Two circuit models are demonstrated: the first modelling the diffusion regime as a hyperbolic tangent function from which apparent 'diffusion coefficients' can be extracted; and the second modelling it as a finite capacitively terminated RC transmission line allowing a clearer resolution of time constants associated with apparent 'charge transfer processes' in PANI.