UConn professor develops electric masks. Here’s how they work.

Connecticut schools may soon allow students to remove their masks, but that’s not stopping Thanh Nguyen.

Nguyen is an assistant professor at the University of Connecticut, specializing in mechanical and biomedical engineering and materials science. He took a not-so-new idea and adapted it for a new purpose.

Piezoelectric materials have been developed for a few years. Pierre and Jacques Curie first demonstrated in 1880 that certain materials, such as quartz, would generate a small electrical charge in response to pressure.

Piezoelectric fabrics use a tiny amount of energy – body movement, perhaps – to generate this electrical charge.

“Piezoelectric material is considered a smart material because when you apply a force to it, when you bend it, twist it, or deform it, it generates an electrical impulse, an electrical charge on the surface,” Nguyen explained. “It has been widely used in many industrial applications, including sensors, transducers and actuators.”

For example, the first sonars were based on piezoelectric technology. Now, Nguyen has applied this century-old principle to masks.

In the masks that Nguyen has designed, there is a piezoelectric filter, and in this case “the force that is applied on the filter is your breathing air,” he said.

“As you breathe, the filter moves back and forth, and that vibration creates a very small surface charge on the filter, and that surface charge is extremely helpful in trapping water droplets,” he said. he declares.

Other masks, such as N95s, prevent the transmission of viruses and bacteria by mechanical means – the space between the filter fibers allows air to circulate, but is too small for the water droplets that transmit diseases like the coronavirus from person to person.

Nguyen’s masks do that too, about as well as an N95, he said. But his masks have the added benefit of the piezoelectric effect, which makes them more effective at stopping disease-carrying water droplets, he said.

They have the added benefit of being biodegradable. N95 masks are mostly plastic, “it’s a polyethylene,” Nguyen said, “just like a plastic bag.”

On the other hand, Nguyen’s masks are reusable. They can be sterilized in a “commonly available ultrasonic water bath, something like a jewelry cleaner,” he said. And, in a landfill, they should degrade in about a year.

Nguyen is growing and plans to start manufacturing in a few months. Its masks should cost a little more than an N95. Right now, he expects his masks to sell for around $10 each.

“If the demand is really high, maybe we can cut the cost in half or maybe a third,” he said.

The process is scalable in size and quantity. Currently, each mask is handcrafted, but Nguyen believes he can create larger, room-sized filters and mass-produce the sizes he needs. The fabric is produced by interweaving microscopic piezoelectric fibers using an “electrospinning” machine which he says is commercially available.

“We can make it automatic so we can produce a lot of this material at the same time,” he said.

It’s still a lot more expensive than a $3 N95, but Nguyen thinks the extra cost is worth it, considering they’re reusable. While there are ways to sterilize and reuse an N95, these are technically single-use, disposable masks.

“If you think about it, you buy a mask but you can use it for a long time, the effectiveness is really good and it’s very stable,” he said. “Economically, you buy one thing, you can reuse it 10 times, you buy the other thing, it’s a bit cheaper, but then you can only use it twice. Of course, you would buy the one you could use a lot more.

Maria D. Ervin