ISSN 1023-1935, Russian Journal of Electrochemistry, 2012, Vol. 48, No. 4, pp. 375–387. © Pleiades Publishing, Ltd., 2012. Published in Russian in Elektrokhimiya, 2012, Vol. 48, No. 4, pp. 413–426. 375 INTRODUCTION As it was shown in our preceding work [1], charge transfer processes with participation of particles capa- ble to reduce/oxidize on the surface of metal clusters included into electroactive polymer films can be described in terms of diffusion equations (for concen- trations of such particles) complicated with accompa- nying electrochemical reactions in the film interior. In the cited paper, it was also mentioned that the same approach might be used in case of pristine polymer films containing populations of different pores, which completely or partially penetrate such films. In our opinion, the necessity of the corresponding consider- ation is stipulated by the well-known fact that real polymer films are porous systems [2–4]. In this con- nection, one can also remind the previously estab- lished data on the hydrazine electrooxidation at Prus- sian blue (PB) modified electrodes [5], The interesting result of that study was the observed dependence of the measured currents on the amount of PB deposited on the electrode substrate. Though the authors of [5] have treated this finding in scope of traditional representa- tions, other two explanations seem also possible. In particular, one could try to explain the observed dependence by assuming that hydrazine molecules are inculcated into the film volume and react with ox– fragments of the film, i.e. a volume electrochemical reaction takes place in the film interior. It is also nec- essary to additionally suppose that the so-called kinetic layer thickness of such volume reaction [6, 7] is significantly higher than the film thickness, so that the maximum currents could be achieved only in the limit of thick films. An alternative explanation can be based on the assumption that the real border between the film and the bathing electrolyte solution exceeds significantly the visible film/solution interface due to a microcrystalline character of PB films [8] or, in other words, the exist- ence of some surface invaginations and/or pores pene- trating the films. If one supposes the hydrazine elec- trooxidation to exclusively proceed on such a physical border, the observed increase of limiting currents with increasing the film thickness can be referred to some deepening of the presumed invaginations and/or pores, which accompanies the rise of the film width. It is well known that such an effect of changing the real electrode surface usually takes place under electrodeposition of metals. One can therefore expect the same phenome- non for electropolymerization processes on modified electrodes. As it will be shown in the next part of the paper, simulation procedures corresponding to the indicated mechanisms coincide in their main physical features, though the conclusions derived for heteroge- Electrical Currents Resulting from Reduction/Oxidation Processes of Tested Particles on “Inner” and “Outer” Surfaces of Electroactive Polymer Films 1, 2 V. V. Malev a, b, z and O. V. Levin a a Department of Chemistry, St-Petersburg State University b Institute of Cytology, Russian Academy of Sciences, St-Petersburg Received March 16, 2011 Abstract—Heterogeneous reactions of tested particles proceeding on electroactive films with different kinds of thin pores are described formally in terms of diffusion equations complicated with an accompanying vol- ume reaction inside the film interior. As it is shown, in polarization curves of such processes, there might appear limiting flows, which are essentially smaller than the limiting diffusion flow of tested particles in the bathing electrolyte. These flows should not depend on a film pores’ topology, but be determined by the ratio of the total surface of pores and the visible film one. The obtained results are compared with those followed for the case when tested particles actually inculcate into the film matrix and react with either ox- or red-frag- ments of the film. Identification criteria of the compared mechanisms are discussed. Keywords: electroactive films, film pores, tested particles, limiting flow, volume and heterogeneous reactions, electrode potential DOI: 10.1134/S102319351203007X 1 Published on the basis of the materials of the IXth International Frumkin Symposium “Materials and Technologies of Electro- chemistry of the XXIst Century” (Moscow, October, 2010). 2 The article was translated by the authors. z Corresponding author: elchem@rbcmail.ru (V.V. Malev).