Electron spin resonance studies of pyrroles in aqueous solution

Abstract

The polypyrrole film electrode was prepared by electrochemical polymerization in aqueous solution. The characteristic signal of radical cations was observed in the electrolysed pyrrole aqueous solution, and the in situ e.s.r. electrochemical study of the polypyrrole film electrode prepared in aqueous solution was quite different from that prepared in acetonitrile, with a Dysonian-type shape. This indicates that the polypyrrole film becomes an electrically conducting form of material consistent with metallic behaviour. The variation of the e.s.r. signal intensity with various potential steps has provided evidence that the polarons and bipolarons in polypyrrole can interchange under certain potentials.