The present study deals with the deposition of plasma polymerized acrylic acid (PPAA) coatings on the surface of polystyrene beads. XI'S analysis showed that the COOH content of the unwashed surface decreased by increasing the power, whereas the resistance to washing was improved weakly. The results showed that the use of an argon pretreatment of PS beads before plasma deposition of AA leads to a strong adhesion between PPAA coating and the underlying PS, reinforcing its stability. The study of the influence of the plasma deposition time clearly showed that the COOH content increased with the plasma treatment time, due to a better coverage of the PS beads. However, the stability of such coatings decreased inversely with the plasma treatment time due to their delamination. (C) 2011 Elsevier Ltd. All rights reserved.