Scientists have shown that the liquid used in the top coat of a disposable face mask is so dense that it can leak out of the pores of the mask when a patient uses it.
The mask washes away with a spray of liquid, which is then passed through a special filter to remove the liquid.
However, if the mask is exposed to air, it can still leak.
The Harvard University study, published in the journal ACS Nano, says that if a patient’s face is exposed when they apply the mask, they could still cause skin damage.
The researchers created a prototype mask to see how the mask would behave if the liquid leaked from the pores.
“If the mask were to be exposed to a large amount of air, then the liquid could be trapped in the pores and would spill out,” said study co-author Mark O’Connell, a postdoc in the Department of Materials Science and Engineering at Harvard.
“However, if a small amount of the liquid were to enter the pores, it would be more stable and would dissipate in the air.”
The researchers then tested the prototype mask with air and water to see if the design could be more sensitive to the presence of air.
They found that the water-based mask is a little more sensitive than air-based masks.
“The solution is to use a thinner layer of liquid that is much more permeable to air,” O’Connor said.
“When it’s sprayed through the filter, the liquid flows in and out of pores, and that’s a way to avoid the possibility of leakage.”
If the researchers had used a thinner material that is not so porous, the mask might have leaked.
“There’s a potential risk that the mask may leak into the skin,” O.J. C. Jones, a professor of biomedical engineering and materials science and engineering at the University of Pennsylvania, said in a statement.
“This could be caused by a small leak from a porous material or by the material leaking into the face or into a tissue, such as skin.”
The mask could still leak if the fluid is too small to penetrate the pores easily, but it is much safer for the skin, according to the study.
The next step is to develop a way of making the mask more efficient.
“Our goal is to design a material that can penetrate pores in a way that’s as thin as possible, so it’s not leaking into skin,” Jones said.