Synergistic study on atomic oxygen-induced erosion of polyethylene with vacuum ultraviolet

Ground-based experimental results on atomic oxygen-induced erosion of polyethylene with simultaneous vacuum ultraviolet (VUV) are reported. In situ mass-loss measurement was made using a quartz crystal microbalance with a mass resolution of 2 ng. A laser detonation atomic oxygen beam source was used to simulate collision energy of atomic oxygen with materials in low Earth orbit. To change relative intensity of atomic oxygen and VUV, the sample was rotated with an axis perpendicular both to the axes of atomic oxygen and VUV. It was observed that the erosion rate of polyethylene was increased 30-100% by a simultaneous VUV exposure depending on the incident angle of atomic oxygen. No contribution of temperature increase was confirmed in the polyethylene erosion. The experimental results, suggested that two reaction pathways exist in the simultaneous atomic oxygen and VUV exposure conditions. It is suggested that the synergistic effect on polyethylene erosion is emphasized in the exposure condition where relative atomic oxygen flux is low against VUV flux.