Degradation of Teflon® film under radiation of protons and electrons

Aluminized Teflon® film (fluorinated ethylene propylene) is commonly used on exterior spacecraft surfaces for thermal control. Synergistic effects of proton and electron radiation on the Teflon film degradation were investigated in terms of ground-based simulation testing. The energy of protons and electrons was chosen in the range of a few tens of kiloelectron volts. The results showed that an absorption band from the near-ultraviolet to the visual region was formed under either proton or electron radiation. But there was no additive effect on reflective property of aluminized Teflon under synergistic radiation of protons and electrons. The effect of simultaneous radiation of protons and electrons was lower than the additive effect of these two charged particles. Under the equal fluence of radiation, the total changes in spectral reflectance were independent from the radiation sequence of protons and electrons. The structural defects induced by protons and electrons were somewhat different. The electrons preferred to activate large molecules and bombard fluorine atoms out of the main chains, forming various free radicals and carbon atoms. Under the radiation of protons, the implantation of protons played an important role in the formation of functional groups. The relation between optical properties and microdefects is discussed.