Effects of ionizing radiation and temperature on hydrophobic self-cleaning photonic coatings

Abstract

Dust contamination is a serious problem for equipment and vehicles for space mission applications. Dust contamination gathers on photonic sensors inhibiting motion and data gathering. In addition, devices that require transparency to light for maximum efficiency such as solar photovoltaic power systems, video cameras and optical or infrared detectors will suffer from the dust accumulation. For example, on the lunar surface, regolith (lunar dust) contamination is a serious problem for equipment and vehicles since the lunar soil has fine texture compared to terrestrial dust particle size distributions. The electrostatic charging of the lunar surface is caused by its interaction with the local plasma environment and solar UV and X-rays induced photoemission of electrons. The lunar thermal environment poses unique challenges to coatings since it is characterized by large temperature variations, long hot and cold soak times, and reduced heat rejection capability due to the presence of the lunar regolith. Fundamental forces (van der Waals) allow certain contamination to adhere to critical photonic surfaces and can be mitigated using various passive coatings phenomenology (hydrophilic to hydrophobic).