Some important physical processes represented by the shape of voltammograms of polyaniline in the phase of oxidation are identified and modelled. The main process, i.e. an angular diffusion by which the motion of conducting polymer subunits take place is described and modelled. To fit a molecular picture of the oxidation process a nontrivial random walk of polymer subunits in configurational space of angles has been performed. A very good agreement between theoretical predictions and experimental data has been obtained. (C) 2007 Elsevier B.V. All rights reserved.