The potential-controlled assembly of 1-dodecanethiol (DT) onto the polycrystalline gold surface from ethanolic solution was studied using in situ methods. The initial stage of DT adsorption and DT him nucleation were carried under potentiostatic control. The anodic polarization speeds up 1-dodecanethiol monolayer formation and increases the structural integrity of monolayers in comparison with those self-assembled at the open circuit potential. Electrochemical impedance spectroscopy measurements have shown that the monolayers are essentially free of pinhole defects, and the electron transfer reaction at the coated Au electrode/electrolyte interface takes place through tunnelling mechanism. (C) 2008 Elsevier B.V. All rights reserved.