Effect of electrode substrate on the morphology and selectivity of overoxidized polypyrrole films

Polypyrrole (PP) films were electropolymerized on glassy carbon (GC) and rough pyrolytic graphite (RPG) electrodes and treated by overoxidation in sodium hydroxide and phosphate buffer. The effects of treatment on film morphology were investigated, including permselective response of treated films. Films grown on GC and RPG were also compared, and it was found that the substrate plays a definite role in the properties of the polymer layer. Differences in response to ionic probes on treated PP electrodes are shown to arise from the porosity of the membranes, which affects the electron density within the film due to the spacing of carbonyl groups introduced during treatment.