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K-State Today

July 13, 2022

Pair of mechanical and nuclear engineering department faculty secure patent

Submitted by Amy Brox

Two faculty members in the Alan Levin Department of Mechanical and Nuclear Engineering have secured a patent for their work on nanopatterned surfaces and methods for accelerated freezing and liquid recovery. 

Amy Betz, assistant dean for retention, diversity and inclusion for the Carl R. Ice College of Engineering and associate professor, and Melanie Derby, recipient of the Hal and Mary Siegele Professorship in Engineering and associate professor, teamed up on the project with the overarching goal of investigating the effect surface structures and coatings have on freezing and frost formation. The project was funded by the National Science Foundation.

In 2015, Betz and Derby published a paper on mixed wettability surfaces that delayed freezing of condensed droplets and suppressed freezing down to a temperature of 21 degrees Fahrenheit as opposed to the regular freezing temperature of 32 degrees Fahrenheit. They hypothesized that physical mechanism delaying freezing was the movement of droplets due to coalescence. To further prove the influence of coalescence on freezing, they wanted to see if a surface that prevents coalescence will accelerate freezing. They used samples manufactured for the project by a collaborator, Edward Kinzel, with regularly arrayed nanopores and nanopillars that pinned droplets and suppressed coalescence. Some of the early data for the project was collected by Cara Snyder, a high school science teacher in Topeka. They found that surfaces that prevent coalescence did in fact accelerate freezing by orders of magnitude.

They also found other very interesting freezing behavior. For example, even though the initial freezing of droplets is accelerated, the subsequent 3D growth is significantly suppressed. They found that the droplets remained optically transparent as they froze and created cubic ice crystals.

Betz and Derby filed for a patent in 2016. While they were able to secure the patent for their nanopatterned surfaces, they never filed a patent for their mixed wettability surfaces that delayed freezing because they published their results before submitting an invention disclosure.

"We didn't even think about filing for patents until we started being contacted by companies after our 2015 paper," Betz said. "Our research is most applicable to cooling and refrigeration technologies, but it may also be used in water collection, cryogenics and optics."

According to the 2020 report from the U.S. Patent and Trademark Office, women are only listed on 21.9% of patents and women are 12.8% of patent holders.

"We are very excited about being an all-women invention team," Betz said.

 U.S. Patent No. 11,346,087 was issued May 31.