Electropolymerisation of pyrrole on copper in aqueous media

Smooth and flexible polypyrrole (PPy) films have been obtained by electrochemical oxidation of pyrrole on an electropolished Cu electrode in an aqueous dodecylbenzene sulfonic acid (DBSA) medium. Cyclic voltammetry (CV) accompanied by X-ray photoelectron spectroscopy (XPS) has been used to characterise the surface modifications of the Cu electrode induced by this treatment. It was found that the electropolished copper surface was partially passivated by Cu2O. This layer reduces Cu dissolution dramatically without prevention of pyrrole electropolymerisation. The interfacial layer between the PPy(DBSA) film and Cu substrate was also studied by time-of-flight secondary ion mass spectrometry (TOF-SIMS). A sulfur-rich layer was observed, indicating the presence of a thin layer of DBSA at the interface. This study offers a fundamental understanding of PPy/copper interfaces and PPy surfaces leading to an improvement in production of adherent PPy coatings on copper electrodes for possible use in electronic and sensing applications. (C) 2003 Elsevier B.V. All rights reserved.