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Coating protects organic materials from photodegradation
05 May 2006
Materials scientists in Spain have used sol-gel technology to develop a UV protective coating, which they say can protect organic materials from light damage.
David Levy and colleagues at the Materials Science Institute of Madrid inserted a benzophenone into ormosil, an organically modified silica that forms well-defined porous networks. The benzophenone chosen has good photostability and strong UV absorption capability. Ormosil is an ideal substrate because its porosity allows high loading, and it can be modified at room temperature.
The resulting matrix creates a transparent UV protective coating without the often encountered problem of high temperature curing. Levy found that photodegradation rates of a fluorescent dye were 14 times slower after it had been coated with the ormosil-benzophenone composite.
Photodegradation occurs when organic materials susceptible to decomposition are exposed to light. Artificial light, such as flash photography, can be just as damaging as sunlight.
The ormosil-benzophenone coating is effective because it absorbs and dissipates UV radiation before it reaches the organic material, according to Levy. He added: 'it can be applied to almost any material exposed to strong light sources. It could even be used to protect artwork in museums from flash photography.'
Christopher Liauw, a Senior Research Fellow in the Division of Chemistry and Materials at Manchester Metropolitan University, welcomed the work. 'This is a novel approach to UV protection that places the UV absorber exactly where it is needed,' Liauw said.
Janet F Crombie
ReferencesP G Parejo, M Zayat and D Levy, J. Mater. Chem., 2006