Enhanced resistance to proton irradiation of poly(dimethylsiloxane) resins through surface embedding of silica photonic crystals

Abstract Poly(dimethylsiloxane) (PDMS) based resins are materials used in large amounts on spacecrafts and satellites. When such materials are exposed to proton irradiation, especially in geostationary environment, they tend to crack and turn yellow, this being detrimental to their operational status. Here we present the elaboration and ageing of hybrid materials made of the embedding of non- or vinyl-functionalized silica nanoparticles (SiO2 NPs) assembled into a photonic crystal at the surface of a PDMS matrix. The influences of the size of the nanoparticles, the thickness of the crystal as well as the grafting density of vinyl moieties on the proton resistance of the materials were studied. The materials maintained the initial transparency of PDMS in a wide spectroscopic range. Transparency of the materials was evaluated using UV-vis-NIR spectroscopy before and after accelerated proton-induced ageing was carried out to simulate part of proton irradiation encountered in geostationary environment. Fourier Transformed Infra-Red-Attenuated Total Reflection (FTIR-ATR) experiments allowed comprehensive study of the mechanisms leading to the stabilization of the materials in terms of cracking and yellowing. Stabilization in regards of cracking was revealed thanks to optical and scanning electron microscopy.