Impedance investigation of the charge transport in film-modified electrodes

Abstract Two kinetic models which can explain the coupling between electrochemical charge transfer and the charge transport in polymer films of film-modified electrodes are analyzed. The first one is based on a diffusion-like process due to the mutual electron exchange between adjacent redox centers. The second one assumes a finite conductivity of the film. The electrochemical impedances characteristic of the models have been derived and also simulated numerically. Some experimental impedance measurements which were obtained from a glassy-carbon electrode modified with a redox-polymer film are reported and discussed in terms of these two models. The influence of film inhomogeneities on the impedance characteristics is also discussed.

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