Polymer article having a thin coating on at least one of its side, characterized in that said coating comprises a first coating of SiOxCyH2 which is a plasma polymerized tetramethylsilane deposited on the surface on said polymer article, the x value being between 0 and 1.7, the y value being between 0.5 and 0.8, the z value being between 0.35 and 0.6 for said first SiOxCyHz coating and a second coating of SiOxCyHz which is a plasma polymerized tetramethylsilane deposited on the surface on said first coating, the x value being between 1.7 and 1.99, the y value being between 0.2 and 0.7, the z value being between 0.2 and 0.35 for said second SiOxCyHz coating and in that the thickness of said first coating is from about 1 nanometer to about 15 nanometers and in that the thickness of said second coating is from about 10 nanometers to about 100 nanometers, preferentially around 30 nanometers.