Face Mask for Protection Against COVID-19: How Effective Are Nanofibers In Terms of Filtration Efficacy, Shield from the Virus?

Scientists at the Southern University of Science and Technology in Shenzhen, China, recently examined the uncertainties in using face masks in terms of efficacy through visualization of nanofibers that interact with exposure to water aerosol.

A Nanowerk report said, since the beginning of the pandemic, the COVID-19 virus has infected over 207 million people globally and has claimed more than four million lives, as per the August 17 dashboard update of the World Health Organization.

Nevertheless, many medical professionals refer to the consequential function of face masks in decelerating the spread of the virus and shielding human health.

Innovations to enhance the efficacy of masks, with increased concentration on nanofiber manufacturing, have led to higher efficacy in filtration, greater comfort, and easier breathing capacity. Nevertheless, the impacts of micro water droplets on the integrity of nanofibers are somewhat unclear.

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Nanofibers for Face Masks

In the study, Visualization of the interaction of water aerosol and nanofiber mesh featured, published in Physics of Fluids, co-author Boyang Yu said when COVID-19 initially took place, face masks were in tremendously short supply in all places, and people came up with their own respective ways "to rejuvenize" used face masks.

Yu added, it was like a contest for chefs involving steaming, boiling, grilling, and even smoking. Also commenting on face masks, the co-author said their intuition told them "this can't be right" and that they need to look into and find out what precisely happened with the nanofibers.

Together with his colleagues, Yu employed high-speed microscopic videos to systematically visualize nanofiber's evolution, made of polymers with different contact angles, mesh sizes, and diameters under water aerosol exposure.

The co-author explained, filming nanofibers is similar to taking baby portraits. They do not like to remain in place for the camera since nanofibers are very flimsy and soft, specifically with the aerosol flow that blows through. Nonetheless, with adequate care, luck, and patience, the co-author said they got nice images for their analysis.

'Aerosol Droplets' Captured

A similar Healthcare Hygiene Magazine report said, the images generated show nanofibers merge permanently during the droplet capture phase and the subsequent liquid evaporation stage, substantially lessening the effective length of fiber for capturing aerosols.

They exhibit hydrophobic and orthogonally woven fibers that can decrease capillary forces and lessen the fiber merging rate.

Co-author of the study Weiwei Deng said they validated three things. The first is that nanofibers are excellent at capturing droplets in an aerosol.

The second is that nanofibers are joined together after capturing the aerosol. And lastly, such an attachment is tight, not to mention permanent, even following evaporation of the captured droplets.

Further Improvement Needed

In their study, the researchers said that wetted fibers are inclined to bond to each other similarly that wet hairs are inclined to bundle together.

It is because the capillary force, which turns prevalent as the size scale shrinks, is very strong for nanofibers.

Furthermore, the study's findings are anticipated to help improve the nanofiber-made face masks' use, design, and fabrication.

They offer direct visual proof for the need for frequent replacement of face masks, particularly in cold environments. Deng explained the winter is coming.

And when it's cold outside, added the co-author, one's breath contains more droplets that may make the nanofiber mesh collapse more rapidly.

Related information about nanofiber in face masks is shown on Brigham Young University's YouTube video below: