The electropolymerisation of 3,4-ethylene-dioxythiophene (EDOT) by cyclicvoltammetry on nickel electrodes was studied in aqueous solution containing EDOT, lithium perchlorate and sodium dodecylsulfate (SDDS). Homogenous blue-dark films are obtained and characterised with scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), their mechanism of formation is analysed in terms of potential value and surfactant concentration. (C) 2003 Elsevier Science B.V. All rights reserved.