SURFACE REACTION OF ATOMIC OXYGEN WITH SPIN-COATED POLYIMIDE FILMS: TEMPERATURE DEPENDENCE OF THE REACTION EFFICIENCY

摘要

The ground-based experimental results of temperature dependence of erosion rate of polyimide and polyethylene films under hyperthermal atomic oxygen beam exposures are reported. The in-situ mass loss measurement was made during the atomic oxygen exposure by using a quartz crystal microbalance (QCM). The polyimide and polyethylene films used in this study were spin-coated on QCM sensor crystals and the shifts in resonance frequency of polymer-coated QCMs were recorded with a mass resolution of 2 ng. A 5 eV atomic oxygen beam was generated with a laser detonation-type atomic oxygen beam source. It was observed that the temperature dependence of erosion rate of polymers was examined in the temperature range of 253 K to 353 K. The Arrhenius plots gave the activation energies of gasification reaction of 10~(-3) to 10~(-4) eV for both materials. It was also observed that the activation energy increased with decreasing translational energy of the beam. It is, thus, confirmed that the erosion rate of polymers in low Earth orbit is temperature independent due to the high collision energy of atomic oxygen.