1 Corrosion protection performance of cold plasma deposited organosilicon coating: effect of surface pretreatments Maryem ESBAYOU 1,2 , Fouad BENTISS 1,2 , Abdelhamid Nyassi 2 , Charafeddine JAMA 1,* 1 UMET-ISP, CNRS UMR 8207, ENSCL, Université Lille Nord de France, CS 90108, F-59652 Villeneuve d'Ascq Cedex, France 2 Laboratoire de Catalyse et de Corrosion des Matériaux (LCCM), Faculté des Sciences, Université Chouaib Doukkali, B.P. 20, M-24000 El Jadida, Morocco Abstract In order to study the corrosion protection behavior of organosilicon coatings prepared using cold remote nitrogen plasma assisted polymerization of 1,1,3,3-tetramethyldisiloxane (TMDSO), the effect of different surface pre-treatment was tested. The structural properties of the deposited films were analyzed using different methods such as Fourier Transform Infrared Spectroscopy (FTIR), 29 Si magic angle spinning NMR ( 29 Si MAS NMR), Scanning Electron Microscopy (SEM), cross-cut, contact angle measurements and profilometery. The corrosion tests were performed by immersing the uncoated and coated carbon steel samples in aerated 3 wt.% NaCl at 30 °C. The protection efficiency against corrosion of the deposited films has been demonstrated by coupling different electrochemical techniques such as open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS). The results clearly demonstrate that the obtained films provide very good barrier against corrosion and show that the protection efficiency depends strongly on pre-treatment conditions. Keywords: TMDSO; Organosilicon coating, carbon steel, PECVD; EIS. * Corresponding author. Tel.: +33-320-434-482; fax: +33-320-436-584 E-mail address: charafeddine.jama@ensc-lille.fr (C. JAMA).