Polypyrrole and polythiophene electrogenerated films were studied in the background electrolyte by potential steps. The kinetic of the oxidation/reduction processes were followed. Both processes have an answer in current density similar to a nucleation process. Nevertheless, an amorphous structure was kept before and after oxidation. Those like nucleation processes were controled by the conditions of generation and the polymer degradation state. They were interpreted as a transition in amorphous phase, controled by the opening of the molecular structure allowing the counterions to penetrate. The movement in one point promotes a chain movement arround, growing along the surface in a sigmoidal shape and promoting an increase in conductivity. The oxidized structure is amorphous, like the reduced one, including counterions. The inverse process (counterions expulsion) is easy and the correlative nucleation like a faster process.
