Researchers at IIT Guwahati have developed a nanotechnology-based coating which can be applied on regular cotton and silk masks. The end result provides greater protection against COVID-19 at a lower cost and higher breathability than N-95 masks, they said in a paper recently published in the ACS Applied Biomaterials journal.

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“A cloth mask is largely porous to aerosol and thus cannot effectively prevent COVID-19 type infection. Though they are still better than wearing no mask, an improved version that would prevent the entry or exit of the aerosol from the modified cloth mask was needed,” explained Arun Chattopadhyay, a professor in IIT Guwahati’s Chemistry department and Centre for Nanotechnology who led the research team. “We have worked on that based on the principle of repulsion of the aerosol by the modified cloth while allowing the air to flow through the mask. A simple coating of the hydrophobic molecule on the silk cloth worked well here.”

While the World Health Organisation has recommended the use of N-95 masks, high cost and low breathability have hampered their usage among large sections of the population. IIT researchers tested the breathability of their new coating by measuring oxygen permeation through their modified silk mask with the help of gas chromatography. They found that the penetration of oxygen reduces by only 22% for the coated mask in comparison to the unmodified silk mask, whereas breathability was 59% lower in an N-95 mask in comparison to the plain cloth mask.

Inexpensive fabrication process

“This is a one-step quick and inexpensive fabrication process that would help in the mass production and distribution of these masks to a large section of the population,” said Prerona Gogoi, a Chemical Engineering student who is cited as the first author of the paper.

These modified masks can also be reused again after being washed with regular household detergent and drying. The other advantage of the new technology is the possibility of further adaptations. For example, it can be used with other additives such as anti-bacterial nanomaterial for additional protection against viruses, researchers said.