Dodecanethiol self-assembled monolayers (SAMs) were formed on copper in aerated and deaerated aqueous micellar solutions of cetyltrimethyl ammonium bromide (CTAB), respectively. The corrosion inhibition effect was investigated in 0.51 mol/L NaCl solution using electrochemical impedance spectroscopy and polarization curves. The surface covered with SAMs was characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and attenuated total reflection Fourier transform infrared spectroscopy. The inhibition efficiency of the SAMs formed in aerated solution and deaerated solution is 99.955% and 99.60%, respectively. During the self-assembly process in aerated solution, CTAB molecules are trapped into dodecanethiol SAMs. The mechanism involved is proposed and discussed. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.013207jes] All rights reserved.