Dr. Peter Tsai, inventor of the electrostatic charging technology that makes the filter media of face masks including medical and N95 was recently featured in this article from the Washington Post, which provides various sources and opinions on constructing DIY face masks.  As more individuals seek to create home-made face masks, Dr. Tsai shares some additional thoughts on important elements to consider:

“Basically, any cloth barrier helps to prevent the spread of the droplets from an infected person and to intercept the droplets before entering a healthy person. A hydrophobic nonwoven layer such as shop towel made of PP (Polypropylene) or PET (polyethylene terephthalate) between two thin layers of fabric such as handkerchief or scarf is an ideal structure for a homemade mask because 1) the droplet will not penetrate through the hydrophobic media to contaminate the wearer’s mouth or nose and 2) nonwoven fabrics have a better filtration efficiency than a woven fabric because nonwovens are composed of fibers with each individual fiber serving to capture particles. Woven fabrics, on the other hand, are composed of yarns or threads, in which fibers are bundled together. Only the fibers exposed on the yarn or the thread surface have the ability to capture particles.

Hydrophilic materials such as wipes, tissues, paper towels, or coffee filters are not ideal for the middle layer of the mask because the droplets in contact with these materials will spread out, penetrate through, and contaminate the wearer’s mouth and nose.  A drop of water on the material can show if a material is hydrophobic or hydrophilic: it is hydrophobic if the drop beads up, hydrophilic if it spreads out.”

 


This excerpt is for informational and educational purposes only and publishes information developed in the course of academic and research work. The information contained herein, in whatever form, does not constitute medical advice, is not intended to be a substitute for medical advice and should not be used as a substitute for medical care and treatment or the applicable recommendations of the Centers for Disease Control or the World Health Organization. The information contained herein is not a substitute for and does not replace any manufacturers’ user instructions or conditions or limitations for using, cleaning, sterilizing or caring for masks, respirators or other personal protective equipment.  Any use of this information is at the user’s own risk and responsibility.
DR. TSAI, THE UNIVERSITY OF TENNESSEE RESEARCH FOUNDATION, AND THE UNIVERSITY OF TENNESSEE DISCLAIM ANY AND ALL EXPRESS OR IMPLIED REPRESENTATIONS OR WARRANTIES REGARDING THIS INFORMATION; DR. TSAI, UTRF AND UT SPECIFICALLY DISCLAIM ANY REPRESENTATION OR WARRANTY THAT SUCH INFORMATION IS FIT FOR ANY PARTICULAR USE.