Preventing UV-light damage of light sensitive materials using a highly protective UV-absorbing coating

Abstract

One of the most important drawbacks of classical and new advanced functional materials for applications outdoors, or in environments with high UV irradiation, is the light induced damage that reduces drastically their effective operation lifetime or durability. This makes protecting light sensitive materials against UV irradiation a nowadays important technological demand in almost every industrial field. This tutorial review incorporates the main aspects of UV damage to materials and describes the recently developed highly effective thin UV-protective coatings, based on UV-absorber molecules entrapped in a Sol-Gel derived ormosil matrix.

Selective UV Reflecting Mirrors Based on Nanoparticle Multilayers

“…[ 12 ] In the case of arbitrary material surfaces, both polymeric and sol-gel coatings embedding one of the abovementioned UV blocking compounds are commonly employed. [ 13 ] In the last few years, visible transparent materials that merge mechanical fl exibility and absorption at certain ultraviolet ranges have been developed by inclusion of the formerly mentioned compounds in polymeric matrices, aiming at creating adaptable coatings for a wide variety of UV sensitive environments. [14][15][16][17][18][19] However, radical species produced as a consequence of UV light absorption by the organic guest compounds degrade the polymer host, rendering the coating useless after some exposure time.…”

Novel approaches to flexible visible transparent hybrid films for ultraviolet protection

“…In general, the more widely spread approach to UV protection, be it in sunscreen lotions or in any materials whose degradation is to be prevented, is based on the use of organic UV absorbers, [18][19][20] which transform the incoming radiation in low energy thermal dissipation by means of photophysical reactions. It is out of the reach of this review to provide an exhaustive list and detailed description of the compounds currently used for this purpose, for which we refer the reader to the comprehensive review published by Levy and coworkers on the subject.…”

“…Recently, a solution was proposed to avoid the mentioned handicap by means of using a transparent inorganic matrix to insert the UV absorber, improving the stability of the film and, simultaneously, keeping the highly efficient UV-absorption. 20 The matrix is now an amorphous, highly porous, and mechanically stable silica network, prepared by a series of hydrolysis and condensation reactions of silicon alkoxides that occur at low temperature and that can eventually be shaped as a film. Although this sol-gel approach solves many of the stability issues observed before and gives rise to matrices capable of incorporating large quantities of organic molecules by adsorption onto the pore walls, it cannot be used to create flexible films.…”

Development of sol–gel formulations for slow release of pheromones

“…Sol-gels are inorganic polymers of metal alkoxides (usually silicates) that exhibit glass properties and are chemically inert (Kandimalla et al 2006;Zayat et al 2007). A three-dimensional gel network is produced by the condensation of partially hydrolyzed components, and its porous microstructure is determined by the rate of particle growth and the extent of cross-linking.…”