Electrochemical nucleation and growth of poly-N-Methylpyrrole on copper

The potentiostatic electropolymerization of poly-N-Methylpyrrole on Cu at 1.5 V, 2.0 V and 2.5 V vs saturated calomel electrode potentials has been carried out to establish the successive steps of polymer coating generation. The chronoamperograms obtained allow the different steps of the nucleation and growth mechanism to be analyzed by fitting the experimental data to the mathematical equations established in the electrocrystallization theory. In all cases a mechanism consisting of a two-dimensional growth at short time followed by a three-dimensional diffusion controlled growth and at longer times a subsequent two-dimensional growth mechanism, with progressive nucleation, is suggested. Scanning electron microscopy micrographs support this mechanism.