Researchers in the United States have come up with the first passive anti-frosting surface which could revolutionise how we handle ice build-up on aircraft, cars, and even roadways.
A study published by Virginia Tech this week in ACS Applied Materials & Interfaces, claims a proof of concept for keeping surfaces 90 per cent dry and frost free indefinitely, without using chemicals or energy.
“For this project, we’re not using any kind of special coating, chemicals, or energy to overcome frost,” the study’s lead author Farzad Ahmadi, told reporters. “Instead we’re using the unique chemistry of ice itself to prevent frost from forming.”
Traditional approaches to de-icing rely on the application of antifreeze chemicals – including throwing salt on roads – or heat.
There are also special coatings that prevent frost formation, but these coatings tend to wear off easily.
The Virginia Tech approach uses structural shaping in the form of a microscopic array of elevated grooves patterned on to untreated aluminium. Ice then forms in stripes, in “sacrificial” low pressure zones.
These low-pressure areas pull moisture from the air onto the nearest ice stripe, keeping the overlapping intermediate areas free of frost, even in humid, sub-freezing conditions.
“The real power of this concept is that the ice stripes themselves are the chemistry, which means the material we use is irrelevant,” said Jonathan Boreyko, an assistant professor in Virginia Tech’s Department of Biomedical Engineering and Mechanics.
“As long as you have that proper pattern of sacrificial ice, the material you use could be virtually anything. So there are a lot of possibilities.”
While the engineers say aircraft wings will be the likely first application, car windshields are also an option for the anti-frosting technology.
Boreyko said the technique is a new application of a well-known principle.
“We’ve known the trick for centuries,” he said. “You put down a low-pressure chemical, like salt, and it keeps everything else around it pretty dry.
“But now we’re making that effect everlasting, and we’re making its distribution rational.”
Bill Condie is a science journalist based in Adelaide, Australia.
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