Nose-hair inspired air filters clean better

Chemical & Engineering News highlighted new air filters inspired by nature that were co-developed by University of Cincinnati chemical engineers.

UC College of Engineering and Applied Science Associate Professor Jonathan Pham and doctoral student Sazzadul Rahat and their research partners developed air filters that work much like your nose to trap particles.

Engineers covered the filters with thin silicone oil coatings that make the surface sticky through capillary force, the attractions between molecules at the surface of a liquid and solid. This force is why dry sand sticks to wet feet much better than dry feet.

“The new air filter is a good example of biomimicry,” Pham said. “Your nose is kind of like an air filtration system. You breathe in a lot of pollen, dust and particulates. Your nose captures a lot of it before it gets into your lungs.”

Researchers put filters with coatings to the test in an indoor baseball stadium, an office building and an exhibition hall and found that they lasted more than twice as long as traditional filters. They also captured significantly more particulates. While strong winds can defeat traditional air filters when particles get sucked back out by a wind gust, the coated filters work when air blows in either direction.

The study was published in the journal Nature. It was led by Professor Sanghyuk Wooh and student Junyong Park from Chung-Ang University in South Korea. The student visited UC for several months to work on collaborative research with Pham’s group. 

Pham has collaborated with some of the paper’s co-authors on other topics since he was a postdoctoral fellow. Now he and his students are continuing to collaborate.

In his lab, Pham and his students work on soft materials and interfaces, relying on polymer science, soft matter and other sciences to craft solutions. Students can study the properties of the materials using an atomic force microscope and a confocal microscope that provide high resolution, force measurement and direct visualization simultaneously, he said.

“A big thing we care about in our group is adhesion and interfaces. The takeaway here is these small particles need to adhere to the filters really well,” Pham said. “And our main contribution is understanding that capillary adhesion.”

Featured image at top: UC engineers developed better air filters with biomimicry. Photo/galitskaya/iStockPhoto