Electrochemical polymerization of 3,4-ethylenedioxythiophene (EDOT) was carried out in presence of two different surfactants, sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB) in aqueous medium. The cyclic voltammograms of the polymers exhibited well-defined redox peaks at E-ox = 140 mV, E-red = 360, and -180 mV for PEDOT/SDS and E-ox 360 mV, E-red = 540, -140 mV for PEDOT/CTAB. The electroactive polymer showed good adherence. The spectroelectrochemical studies were carried out on ITO glass plate at various applied potentials. The oxidized PEDOT/CTAB was opaque blue in color and the reduced form was transparent yellow in color. Electrochromic parameters such as electrochromic efficiency (or coloration efficiency), stability (or cycle life), and optical contrast (or write-erase efficiency) and stability were determined and presented. The in situ conductance was measured at applied potentials ranging from -0.6 V to 0.7 V. The polymer was resistive initially at -0.6 V (7.5 x 10(-5) S cm(-1)) and reached maximum conductance of 1.7 x 10(-3) S cm(-1) at 0.5 V in presence of SDS. The polymer formed with CTAB exhibited high resistive behavior. The surface morphology characteristics were also studied. (c) 2007 Wiley Periodicals, Inc.