A complete and permanent hydrophilic modification of poly (ethyleneterephthalate) (PET) films is achieved by argon-plasma irradiation, subsequently grafting acrylic acid (AA) in vapor phase onto their surface. Both Ar plasma irradiation alone and post grafting AA rendered a complete hydrophilicity to PET surfaces. However, the hydrophilicity of the PET surface, only treated with the Ar plasma, is not permanent. In contrast, PET films, irradiated by the Ar plasma, exposed to air, and subsequently grafted with AA monomer, are permanently hydrophilic. Degradation of polymer chains on the plasma-irradiated surface is proportional to time of exposure
