LOUISVILLE, Ky. — An N95 mask that can be disinfected by simply throwing it into a washing machine would solve a lot of problems for those on the frontlines of the coronavirus.
Soon, it could be a reality thanks to research and development from the University of Louisville's Conn Center for Renewable Energy Research and Advanced Energy Materials, LLC (ADEM).
The partnership has led to a patent-pending reusable mask to filter COVID-19 droplets and other airborne particles and viruses. The mask could also be more efficient because it can be machine-washed and dried to disinfect.
Conn Center's Director Mahendra Sunkara said the mask will soon undergo tests in a certified lab to receive N95 certification so it can be used in medical facilities.
The Conn Center is focused on renewable energy research, and one of the areas of focus is energy storage. Metal foils coated with inorganic nanomaterials are used as electrodes in lithium-ion batteries in the center's lab. However, the pandemic sparked another use for the coating right now, a filter for a new kind of N95 mask.
Sunkara says most current N95 mask filters are made of thick nonwoven polymer fibers.
"And when they are nonwoven, they leave big openings," Sunkara explained. "And in order to capture the small particles, they actually put electrostatic charge. They charge the fibers up.”
That charge acts like a magnet so the COVID-19 virus sticks to it, and that’s how it’s filtered.
The prototype masks Sunkara and his team developed do not require an electrostatic charge because the filter is made with nanomaterial. The diameter of a nanoparticle is so small it’s hard to imagine.
"So when you talk about nanometer, it’s a billionth of your size of hair so human eye, you cannot see it. Only [you can see it] we use these electron microscopes to see a magnified image," Sunkara said.
A manufacturing machine at the Conn Center is coating fabric with nanosolution to create the filter for the masks.
“So you have a very high surface area, nanofilter network, so anything that comes through it will get stuck, especially with the [COVID-19], will get stuck with this inorganic material," Sunkara told Spectrum News 1.
With openings too small for viral particles to pass through, the nanofilter doesn’t need an electrostatic charge. That's a huge advantage because it means masks can be machine-washed and dried to disinfect and then re-used. If current N95 masks are washed, Sunkara said its charge is removed.
“And if you remove the charge, the efficiency of that filtration will go down, and that’s the reason they aren’t washable," Sunkara explained.
The masks can also be disinfected using a low energy ultraviolet (UV) light source.
Conn Center partnered with ADEM, a company co-founded by Sunkara that manufactures nanomaterials.
ADEM made the mask prototypes and will soon mass-produce them.
Sunkara said prototype testing so far, for breathability, airflow, and liquid droplets, has shown promise. However, to be a certified N95 mask used in medical facilities, it needs the National Institute of Health and Occupational Safety (NIOSH) certification, which Sunkara expects in a few weeks.
“The actual test will come from an independent testing lab with a certified procedure, and that is what we are undergoing right now," Sunkara told Spectrum News 1.
In two months, Sunkara said the certified N95 nanofilter masks should be available to the medical industry. He said the masks will also be available for non-medical commercial sales, such as companies that need masks for employees returning to work, in a month. However, those won't have the NIOSH N95 certification.
Once, the masks are available for the market to the medical industry, Sunkara said Kentucky will get priority.
"The entire team would be extremely happy that they are actually part of the solution,” Sunkara said.