PRODUCTS IN SOLUTION DURING ELECTRODEPOSITION OF POLYPYRROLE

Oligomers of pyrrole accumulated in aqueous solution during the anodic oxidation of pyrrole at stationary and rotating electrodes have been identified and separated using UV-visible spectroscopy and chromatographic techniques. Oligomers of up to nine pyrrole units have been observed in stagnant solutions, concurrently with polypyrrole deposition onto the electrode surface. Stirring strongly inhibits accumulation of oligomers longer than three monomeric units and reduces the amount of polypyrrole film deposited, indicating that the establishment of nuclei for polymer growth occurs by precipitation of oligomeric species formed on the electrode surface and accumulated in its vicinity.