MOSCOW, April 28 /TASS/. Researchers from the laboratory of photonics and microfluidics of Tyumen State University (TyumSU) together with University of Loughborough (UK) suggested a novel tool for particle weeding from the surfaces of various materials.

According to TyumSU press service, it was exemplarily proposed to apply this method for purification of surfaces during onboard experiments on flying vehicles modeling gravity-free conditions.

"Suggested technique has been already tested for various combinations of polymeric, talc, and ceramic particles sized between 1 and 100 ·m supported on glass, plastic, or carbolite, with purification efficiency reaching 95% in most cases", the press service said.

"Removal of micro-and nanoparticles from the work surfaces is an important scientific and technical task," said Natalia Ivanova, assistant radiophysics professor of the Tyumen university. Very often such surfaces are located in hard-to-reach places, and could be additionally very sensitive to mechanical, chemical, and thermal exposures, and hence require special purification methods. For instance, common air blowing could transform dust particles on optical elements to "an abrasive material".

Currently, for purification of delicate surfaces, the laser ablation methods are applied based on the explosive thermal expansion of materials or explosive boiling of the thin liquid film under the laser beam. However, this approach is limited, as powerful light impulses often cause the destruction of the purified surface. The Russian-British scientific team invented how to avoid the above-mentioned drawbacks of laser ablation.

Fist, a thin layer of wetting liquid on the particle-contaminated surface is applied, followed by focused laser beam causing the recession of liquid in a beam impact point. As a result, the currents appearing in the liquid pick up the tiny contamination particles and take them away form the heated zone.

Importantly, the maximum heating temperature of the surface does not exceed 80 degrees Centigrade, allowing for nondestructive purification of thermosensitive surfaces requiring gentle treatment. This development could be useful for refining various optical parts of devices, particularly in a zero-gravity environment.

The research has recently appeared in the Journal of Colloids and Interface Science. This work is a part of the European Space Agency's (ESA) project titled "Development of techniques for removing nanoparticles from surfaces of arbitrary texture for experimental application in microgravity conditions."