Reusable Face Mask Could Help Remedy Worldwide Shortage

A novel nano-filter face mask that maintains excellent filtration efficiency, even after multiple washing cycles, could help alleviate global supply shortages.

Developed at the Korea Advanced Institute of Science and Technology (KAIST; Daejeon, Republic of Korea), the nano-fiber mask is manufactured via an insulation block electrospinning process that fabricates orthogonal nanofibers with a diameter of 100~500 nm by controlling their spatial alignment. The unidirectional nanofiber structure can thus minimize air pressure delivery toward the filter and maximize filtration efficiency.

Existing masks fail to maintain air filtration since their electrostatic function disappears when exposed to water. In contrast to these disposable masks, which lack nano-fibers, the new masks are water resistant, with no deformation in the nano-membrane structure, even following 20 repeated hand washes, and despite soaking the masks in an ethanol solution for more than three hours. In addition, following 20 repeated bactericidal tests, the nano-fiber mask still exhibited more than 94% filtering efficiency. The reusable face mask could thus help relieve the challenges arising from the supply shortage of disposable face masks.

“We believe that this mask can be reusable for about a month even after washing in ethanol. The inner filter can also be replaced. This technology will solve the mask scarcity issue and environmental impact of mask waste,” said professor of materials science and engineering Il-Doo Kim, PhD. “We found that the mask filters out up to eighty percent of 600-nanometer particles, even after undergoing a bending test more than 4,000 times.”

Past experiences with severe acute respiratory syndrome (SARS), H1N1 swine influenza, and Middle East respiratory syndrome (MERS) indicate that surgical masks have been most widely adopted by the public as personal protective measure, despite controversy on their effectiveness. The most common face masks are disposable ones, originally made for filtering out up to 94 or 95 percent of fine dust, referred to as N94 or N95 masks.

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Korea Advanced Institute of Science and Technology