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This may look like a standard mask but it has a special disinfectant coating that allows it to kill pathogens as well as protect against them.

Helen Zha is an  assistant professor of Chemical and Biological Engineering at RPI.

Edmund Palermo is an associate professor. Materials Science and Engineering at RPI.

TROY — The COVID-19 pandemic unleashed a wave of innovation in healthcare technology, and a group of Rensselaer Polytechnic Institute researchers were participants in that trend.

Now, one of the developments from the school may be ready for prime time.

Helen Zha and Edmund Palermo devised a face mask that not only protects against exposure to germs and viruses such as coronavirus, but also kills pathogens on contact.

The antiviral, antibacterial N95 masks can potentially be worn for longer periods of time, too, which could reduce waste.   Zha, an assistant professor of chemical and biological engineering and a member of RPI’s Center for Biotechnology and Interdisciplinary Studies (CBIS), worked with Palermo, an associate professor of materials science and engineering and a member of the Center for Materials, Devices, and Integrated systems (cMDIS), to develop the face masks.

“This was a multifaceted materials engineering challenge,” Palermo said in an email. “We think the work is a first step toward longer-lasting, self-sterilizing personal protective equipment.”

The mask was developed by grafting broad spectrum antimicrobial polymers onto the polypropylene filters used in N95 face masks. 

 “The active filtration layers in N95 masks are very sensitive to chemical modification,” Zha explained in an email.   Zha and Palermo, along with other researchers from Rensselaer, Michigan Technological Institute, and the Massachusetts Institute of Technology, attached quaternary ammonium polymers to the fiber surfaces of nonwoven polypropylene fabrics using ultraviolet grafting.

Quaternary ammonium is commonly used in disinfectants.   The fabrics were donated by Hills Inc., a Florida-based fiber manufacturer, courtesy of Rensselaer alumnus Tim Robson. 

“The process that we developed uses a really simple chemistry to create this non-leaching polymer coating that can kill viruses and bacteria by essentially breaking open their outer layer,” said Zha. “It’s very straightforward and a potentially scalable method.” 

The team used only UV light and acetone, a blending agent, in their process, which are widely available, to make it easy to implement.

That process can be applied to already manufactured polypropylene filters, rather than necessitating the development of new ones.  

The active filtration layers in N95 masks are sensitive to chemicals, Zha explained. 

“It can make them perform worse in terms of filtration, so they essentially no longer perform like N95s. They’re made out of polypropylene, which is difficult to chemically modify. Another challenge is that you don't want to disrupt the very fine network of fibers in these masks, which might make them more difficult to breathe through.”

The team did see a decrease in filtration efficiency when the process was applied directly to the filtration layer of N95 masks, but the solution they found is straightforward.

The user could wear an unaltered N95 mask along with another polypropylene layer with the antimicrobial polymer on top.

The project was funded with a National Science Foundation Rapid Response Research grant in 2020, when N95 masks were in short supply.

The mask was recently written up in Applied Materials and Interfaces, a peer-reviewed journal of the American Chemical Society.

In the future, manufacturers could make a mask with the antimicrobial polymer incorporated into the top layer.

The RPI researchers don’t have plans to commercialize the development, but this was an open access project meaning manufacturers could adopt the technique on their own.

“It is our hope to make this information widely available for private and public institutions to use for future research and technology development,” said Zha.

“We certainly hope our work helps enable commercial realization of such self-disinfecting face masks.”

Rick Karlin covers the environment and energy development for the Times Union. Has previously covered education and state government and wrote about natural resources and state government in Colorado and Maine. You can reach him at  rkarlin@timesunion.com or  518-454-5758.