Full-electrochemical preparation of conducting/insulating binary polymer films

Binary polymer films consisting of an insulating polymer and a conducting polymer have been successfully prepared by sequential electropolymerization of the parent monomers. The insulating polymer (polyacrylonitrile or polyethylacrylate) is formed under cathodic polarization in a potential range where the growing chains are chemically grafted onto the nickel or carbon electrode. The conducting polymer (polybithiophene or polypyrrole) is formed by electrooxidation of the parent monomer. The electrochemical reactions and the electrochemical properties of the films have been analyzed by cyclic voltammetry and chronoamperometry. The influence of the main experimental parameters on the composition and morphology of the films has been investigated by X-ray photoelectron spectroscopy and atomic force microscopy. This approach strongly improves the adhesion of the conducting polymer as a result of its combination with the grafted polyacrylonitrile. This combination of insulating and conducting polymers is a way to tune the electroactivity of the conjugated chains.