New frost-reduction technology inspired by desert beetle

BLACKSBURG, Va., Jan. 22 (UPI) -- Materials scientists at Virginia Tech have developed a new frost-reduction technology that could be employed on airplane wings and windshields.

The technology, which limits the growth of frost, was inspired by the Namib Desert beetle, famous for its ability to survive and collect water in one of the hottest and driest places on Earth.

Standing water in the Namib Desert, a coastal desert in southwest Africa, is nonexistent. The Namib Desert beetle, or fogstand beetle, survives by capturing airborne water on its shell. Bumps on the top of the beetle's shell encourage moisture droplets to form, while its smoother sides repel moisture. The juxtaposition helps channel the condensation directly to beetle's mouth.

Researchers at Virginia Tech mimicked the strategy to confine frost formation by overlaying water-attractive patterns on a slick water-repelling surface. The microfabrication patterns are created by chemical treatments using a technique called photolithography.

Frost forms as tiny water droplets freeze and bridge connections with nearby droplets. If these droplets can be kept apart, and confined to small surface areas, frost will fail to form.

"Fluids go from high pressure to low pressure," Jonathan Boreyko, an assistant professor of biomedical engineering and mechanics at Virginia Tech, said in a press release. "Ice serves as a humidity sink because the vapor pressure of ice is lower than the vapor pressure of water. The pressure difference causes ice to grow, but designed properly with this beetle-inspired pattern, this same effect creates a dry zone rather than frost."

Boreyko and his research partners at Oak Ridge National Laboratory tested the anti-frost technology on a limited scale, but they hope it could eventually be deployed at an industrial scale.

"We made a single dry zone around a piece of ice," Boreyko said. "Dew drops preferentially grow on the array of hydrophilic dots. When the dots are spaced far enough apart and one of the drops freezes into ice, the ice is no longer able to spread frost to the neighboring drops because they are too far away. Instead, the drops actually evaporate completely, creating a dry zone around the ice."

The technology could save time, money and energy in aerospace and wind energy industries, where large amounts of harsh chemicals are currently used to defrost airplane wings and wind turbines.

The beetle-inspired technology is described in a new paper, published this week in the journal Scientific Reports.