Continuous measurement of the proton generation at an anodically growing polypyrrole layer

Abstract

Potentiodynamic electropolymerization of pyrrole was performed at the Pt disc of a rotating ring-disc electrode in acetonitrile electrolyte. At the ring electrode, a cathodic wave could be monitored at constant disc potential with a half-wave potential of − 0.25 V (vs. SSCE). The curve is interpreted in terms of the reduction of protons, which are released in the course of the electropolymerization process. Possible reduction of soluble intermediates, originating from the monomer, is excluded. The method opens the possibility of the continuous determination of the proton/electron stoichiometry (α). However, the accuracy of this measurement is hampered by the occlusion of acid in the pores of the growing polymer film. A method for the correction of this effect is presented. The corrected α's preclude a low degree of polymerization.