Researchers at the University of Cincinnati decided to test three common fabrics — cotton, polyester and silk — to determine which is best not just for PPE, but also to wear by itself as a face mask.
The UC team tested not only each fabric’s hydrophobicity — ability of a material to repel small liquid droplets, thereby preventing the penetration and absorption of droplets — but also their breathability and their functionality after cleaning.
“These two additional properties are particularly advantageous for face coverings and can facilitate their use by the general public,” the researchers wrote in their study, published recently in the journal Plos One.
Although cotton fabric is breathable, it absorbs water.
“We found that cotton materials are hydrophilic, and readily allow droplets to rapidly penetrate and saturate the fabric like a sponge,” the researchers wrote. “Therefore, face coverings made out of these materials may quickly become reservoirs of virus and act as conduits for viral transmission when worn, even after a short time.”
Polyester not only absorbed water, but also was difficult to breathe in.
“Face coverings made out of polyester face these same limitations, as we found it to be hydrophilic like cotton,” the researchers concluded. “Therefore, cloth and polyester face coverings appear to be more suitable for brief, one-time use.”
In contrast, they wrote, “silk’s hydrophobicity and lack of capillary action, can make it a more advantageous material for face coverings that are also thin, light, and breathable.”
In its summary, the team wrote: “We suggest that silk has untapped potential for use during the current shortage of PPE in the ongoing COVID-19 pandemic and for future health emergencies. Our laboratory-based study highlights the practicality of using current commercially available 100% silk material as a resource for producing protective coverings that can extend the lifetime of N95 respirators, and as a fabric for fashioning face coverings for the general public.”