Morphology and properties of polypyrrole electrosynthesized onto iron from a surfactant solution

The morphology of polypyrrole (PPy) deposits during electrosynthesis onto iron electrodes in sodium bis(2-ethylhexyl) sulfosuccinate (AOT) solutions have been investigated using Scanning Electron Microscopy (SEM). At the early stages of electrosynthesis, fibrillar, toroidal and globular forms are observed while polymerization at longer times leads to a closely packed deposit. The effects of electropolymerization parameters on the obtained morphology are discussed. It is proposed that electropolymerization rate and polymer stiffness are important factors in controlling the morphology. Electrochemical investigations demonstrate that toroid-shaped deposits present electrochemical activity. The experimental results indicate that a gelatinous product, formed as a result of iron dissolution, grows simultaneously with PPy. (C) 2009 Elsevier B.V. All rights reserved.