c!sz3 __ 5% @ KIUMI zyxwvutsrq B Beam Interactions with Materials 8 Atoms ELSEVIER Nuclear Instruments and Methods in Physics Research B I31 (1997) 205-210 Oxidation and ablation of polymers by vacuum-UV radiation from low pressure plasmas A.C. Fozza a, J. Roth a, J.E. Klemberg-Sapieha a, A. Kruse b, A. Hollkder ‘, M.R. Wertheimer a, * zyxwvutsrqponmlkjihgfedcbaZYXWVUTSR ‘I Groupe des Couches Minces (GCM ) and Department of Engineering Physics, bole Polytechnique, Box 6079, Station Centre-Ville, Montreal, QC HC3 3A7, Canada h Fraunhofer-Institute for Applied Materials Research, D-28717 Bremen, Germany ’ Fraunhofer-Institute for Applied Polymer Research, D-14513 Teltow, Germany Abstract Low-pressure glow discharge plasmas are increasingly used as an effective method for the surface modification of polymers; they can also serve in the laboratory to simulate low Earth orbital environment (LEO). Although Vacuum-Ultra- violet (VUV, A < 200 nm) is an important component of plasma environment, only few studies have focused on its effects so far. The emission from low-pressure microwave plasma in the VUV-UV regions was investigated in order to use this plasma as light sources for the study of the VUV/UV effects on various polymers (polyethylene, polymethylmethacrylate, etc.) or high molecular weight oligomers (hexatriacontane). We have employed a quartz crystal microbalance (QCM) in order to measure in situ the net mass change of the polymeric films exposed to VUV/UV radiation originating from hydrogen plasmas. Measurements were made with the specimens in vacuum, or immersed in low-pressure oxygen, directly exposed to the VUV/UV (perpendicular to the radiation flux), or only to the VUV-generated atomic oxygen, A0 (parallel to the radiation flux). Following irradiation, samples were analysed by X-ray Photoelectron Spectroscopy (XPS), in order to study the evolution of the oxygen content and of the various functional groups. PAC.% 61.82.P~; 81.65.-b; 52.70.K~ Kevwords: Low pressure plasmas; Vacuum-ultraviolet; Polymer oxidation 1. Introduction Low-pressure plasmas have been used in electron- its industry for many years, and are now increas- ingly employed as an effective method for improving * Corresponding author. Fax: + I-514-340-3218; email: mw- ertheimer@mail.polymtl.ca the surface properties of polymers (adhesion, wetta- bility, etc.), essentially without affecting the bulk properties of the material [1,2]. Nevertheless, due to the complexity of plasmas, the mechanisms involved in their interaction with polymers are not yet well understood. Low-pressure plasmas can also serve in the laboratory to simulate certain conditions in outer space, especially those of low Earth orbital (LEO) spaceflight, 200 to 700 km in altitude [3,4]; long-term 0168-583X/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved PII SOl68-583X(97)00154-7 III. PHOTON/ELECTRON/PROTON IRRADIATION