The brush model of the polymer films—analysis of the impedance spectra of Au,Pt|poly(o-phenylenediamine) electrodes

In the “brush model” of polymer modified electrodes it is assumed that the polymer film consists of short and long polymer chains forming bundles in such a way that only a small part of the metal substrate surface is covered by the polymeric material. The results of electrochemical impedance spectroscopy, cyclic voltammetry and surface stress measurements confirm that a brush-like ordering of the polymer chains on the metal surface is a realistic description of the surface film structure. Physicochemical parameters obtained from electrochemical impedance spectra for poly(o-phenylenediamine) films on platinum in contact with 1 M HClO4 or 0.5 M H2SO4 solution were analyzed on the basis of the brush model. The characteristic parameters derived from the impedance spectra of different electrodes were compared.