Scientists from Virginia Tech developed the world's first passive anti-frosting surface that can keep surfaces 90 percent dry and frost free indefinitely without any chemicals or energy inputs.
The study published on Monday in ACS Applied Materials & Interfaces demonstrated the proof of concept to resist ice buildup that can cost consumers and companies billions of dollars every year.
"Frosting is a big issue, and researchers have been working to solve this problem for years," said Farzad Ahmadi, a doctoral student at Virginia Tech and the study's lead author.
Traditional approaches of defrosting went to antifreeze chemicals or energy inputs, like heat. New advances are special coatings that prevent frost formation, but those coatings aren't durable and tend to wear off easily.
"Instead we're using the unique chemistry of ice itself to prevent frost from forming," said Ahmadi.
The researchers created their anti-frosting surface on untreated aluminum by patterning ice stripes onto a microscopic array of elevated grooves.
The microscopic grooves act as sacrificial areas, where stripes of intentional ice form and create low pressure zones and these low-pressure areas pull nearby moisture from the air onto the nearest ice stripe, keeping the intermediate areas free of frost, even in humid, sub-freezing conditions.
These sacrificial ice stripes make up only 10 percent of the material's surface area, leaving the remaining 90 percent completely dry, according to the study.
"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 the Department of Biomedical Engineering and Mechanics at Virginia Tech.
The researchers see immediate applications for the technology in the heating ventilation and air conditioning industry, where the outdoor heat pumps and fan systems already utilize a pattern of micro-fins on their surfaces. Manufacturers would just need to apply the right pattern of grooves on those fins to keep frost from building up inside the systems.
The technology can be applied to airplane wings and car windshields, according to the researchers.
Also, it may help to offset traditional methods of fighting ice that carry troubling implications for the environment. It takes thousands of gallons of antifreeze chemicals to defrost the wings of one airplane for a single flight. Those chemicals run off into groundwater or get dispersed into the air as tiny droplets.