A surface and electrochemical study of polypyrrole coated on stainless steel and copper

The micro-contact printing process (μCP) offers an alternative route for the formation of conducting polymer structures on various substrates for application in polymer-based electronic devices. Understanding the surface and interface chemistry of the polymer/substrate system is a vital element in the production of adherent polymer patterns via μCP. In the present study, electrically conducting polypyrrole films doped with dodecylbenzenesulfonic acid, PPy(DBSA), have been electropolymerised on stainless steel and copper substrates in aqueous media. PPy(DBSA)/metal interfaces and PPy(DBSA) surfaces have been characterised by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). An electrochemical study of PPy(DBSA) growth has been carried out by cyclic voltammetry (CV). Iron and copper were detected at the polymer/electrode interfaces indicating their dissolution from the stainless steel and copper substrates, respectively, during electropolymerisation. In addition, a thin layer of DBSA was observed at the polymer/electrode interface. The effect of growth potential on doping level was also investigated. Adherent PPy coatings on the metal electrodes have been produced and the doping level tailored for optimisation of electroactive devices produced via μCP.