Tiny particles shield sunlight

17 Jun 2002

Light-absorbing nanoparticles could feature in applications that are as diverse as suntan lotions and electronic circuits.

Australian scientists have created particles that are only 10 nm in diameter and absorb ultraviolet light. Terry Turney from Australia's national science agency CSIRO claims that his powders are ideal for a range of applications because they are cheap, easily dispersed in other materials and compatible with different additives.

By controlling the surface chemistry of these nanoparticles, Turney can alter their properties to suit the purpose. "Their application is limited only by imagination," said Turney. "They can be used in sunscreens and cosmetics to protect our skin against ultraviolet rays and also protect plastics and bottles from ultraviolet weathering and photodegradation." Turney believes the nanoparticles could also be useful in drug-delivery methods and electronic and phosphor applications.

Turney maximizes the nanoparticles' ability to absorb ultraviolet light by adjusting the particles' size. "The particles are so small they let visible light through and thus appear transparent," said Turney. "This means that sunscreen [containing these nanoparticles] doesn't look like the war-paint of other sun lotions."

Working with Australian company Micronisers, CSIRO has developed the particles for sunscreens and claims to have already captured 60% of the Australian suntan-lotion market. The new sunscreen products will soon be available in Europe and the US.