Hybrid sol-gel materials for realization of radiation protective coatings-a review with emphasis on UV protective materials

This review reports on hybrid sol-gel coatings used for radiation protective purposes. The different types of electromagnetic radiation are usually distinguished by their wavelength, frequency or photon energy. There is a broad range of types of radiation that humans, materials or electric devices are exposed to, starting from radio waves, microwaves, infrared radiation, visible light, UV light, X-ray and gamma-ray radiation. Gamma-ray radiation is thus at the end of the electromagnetic spectrum with smallest wavelengths, highest frequencies and highest photon energies. Protection against radiation make sense, as it can pose health risks or interfere with technical and electronic equipment for example. Radiation protection can be realized by materials that are able to absorb or reflect the radiation, which leads to a considerable reduction in radiation transmission. These radiation protection materials are specific to different types of radiation or spectral widths, e.g., a material with excellent protective properties against UV light is not automatically suitable for protection against infrared light. The main aim of this review article is to report, what types of hybrid sol-gel materials can be used to provide ideal protection against a specific category of radiation. Additional to the broad view on all types of radiations, focusing in particular on materials exhibiting UV protective properties.