Investigation of the Surface of Poly(ethylene terephthalate) Films Modified by Vacuum Ultraviolet Irradiation in Air

This paper reports on the results of measuring the changes in the characteristics of the surface of poly(ethylene terephthalate) films upon radiation-induced oxidation of the polymer under vacuum ultraviolet irradiation in an oxygen-containing medium. The films were irradiated by light from a sealed-off deuterium lamp with the maximum photon energy within the band (10 +/- 1 eV) in air under conditions where thermal destruction of poly(ethylene terephthalate) could be ignored. The functional relationship between the decrease in the film thickness and the growth of surface irregularities in the course of photoetching was established from measurements of the optical transmission spectra T(lambda) of the films and investigations of the surface microrelief by atomic-force microscopy. The hydrophilic properties of the surface of the sample regions irradiated with different doses were examined by measuring the contact angle.