Imagine a reusable face mask that protects wearers and those around them from COVID-19, is comfortable enough to wear all day, and stays in place without frequent adjustment.
In a new study, researchers have designed a new mask intended to do just that. They are providing the plans so individuals and manufacturers can make it.
The research was conducted by a team at the Georgia Institute of Technology.
The modular Georgia Tech mask combines a barrier filtration material with a stretchable fabric to hold it in place.
Prototypes made for testing use hook and eye fasteners on the back of the head to keep the masks on, and include a pocket for an optional filter to increase protection.
After 20 washings, the prototypes have not shrunk or lost their shape.
The fundamental flaw in existing reusable cloth masks is that they — unlike N95 respirators, which are fitted for individual users — leak air around the edges, bypassing their filtration mechanism.
That potentially allows virus particles, both large droplets, and smaller aerosols, to enter the air breathed in by users, and allows particles from infected persons to exit the mask.
The leakage problem shows up in complaints about eyeglasses fogging up as exhaled breath leaks around the nose, making people less likely to wear them.
The fit problem can also be seen in constant adjustments made by wearers, who could potentially contaminate themselves whenever they touch the masks after touching other surfaces.
To address the leakage challenge, the team created a two-part mask that fastens behind the head like many N95 respirators.
The front part — the barrier component — contains the filtration material and is contoured to fit tightly while allowing space ahead of the nose and mouth to avoid breathing restrictions and permit unrestricted speech.
Made from the kind of moisture-wicking material used in athletic clothing, it includes a pocket into which a filter can be inserted to increase the filtration efficiency and thereby increase protection. The washable fabric filter is made of a blend of Spandex and polyester.
The second part of the mask is fashioned from stretchable material.
The stretchable part, which has holes for the ears to help position the mask, holds the front portion in place and fastens with conventional hook and eyelet hardware, a mechanism that has been used in clothing for centuries.
Beyond controlling air leakage, designing a better mask involves a tradeoff between filtration effectiveness and how well users can breathe.
The stretchable part of the mask is made from knitted fabric — a Spandex/Lyocell blend — to allow for stretching around the head and under the chin.
The researchers used a woven elastic band sewn with pleats to cover the top of the nose.
The researchers made their mask prototypes from synthetic materials instead of cotton.
Though cotton is a natural material, it absorbs moisture and holds it on the face, reducing breathability, and potentially creating a “petri dish” for the growth of microbes.
The team will make the specifications and patterns for their mask available to individuals and manufacturers.
The necessary materials can be obtained from retail fabric stores, and the instructions describe how to measure for customizing the masks.
One author of the study is Sundaresan Jayaraman, the Kolon Professor in Georgia Tech’s School of Materials Science and Engineering.
The study is published in The Journal of The Textile Institute.
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