Surface Modification of Polyethylene Terephthalate with Excimer UV Radiation

Abstract

Photochemical dry etching and surface modification of polyethylene terephthalate (PET) was investigated with an incoherent excimer UV source, employing a dielectric barrier discharge in krypton chloride to provide intense narrow-band radiation at λ=222 nm (KrCl*). The roughness of the exposed PET was measured with a stylus profilometer. The morphology of the irradiated PET films was investigated by scanning electron microscopy (SEM) after different exposure times and the roughness of PET can be controlled by UV intensity and exposure times. Etching rate is 40 times higher than that for photochemical etching of PET with a conventional mercury lamp. The chemical changes in the UV-exposed PET surface layer were determined using x-ray photoelectron spectroscopy (XPS) by measurement of the intensity of the C—C, C—O and O—C=O bonds after irradiation with the KrCl* excimer lamp.