Exclusive interview with the Inventor of N95 Mask Filter Dr. Peter Tsai

Jul 27, 2020


"I'm not a top scientist. My invention was recognized internationally because of the recent pandemic."

A small piece of N95 mask has become the amulet for medical workers under the serious Covid-19 outbreak. Dr. Peter Tsai, a Taiwanese former professor of materials science at University of Tennessee, is the inventor of the core technology behind N95 mask. Dr. Tsai was interviewed by the Ministry of Science and Technology (MOST) Center for Global Affairs and Science Engagement (GASE) on what he referred to as the "ordinary" technology of N95.

The core technology: N95 mask has become the amulet for medical workers

Dr. Tsai explained that the earliest version of the mask was a flat structure without sealing function on the edges. In the 1970s, the creator of molded bra cup, Décor Editor of House Beautiful Magazine, invented a three-dimensional respirator masks with edge-to-edge adhesion. The N95 respirator met the American mask standard with up to 95% dust particles filtration efficiency. The mask was originally worn by construction workers to prevent inhalation of dust; however, it has become an essential medical supply made from the electrostatic meltblown fabric invented by Dr. Tsai. This technology came out in 1992 and was originally used to improve air filtration, and then applied to N95 masks later, which greatly improved the filtration efficiencies of dust, bacteria and viruses to more than 95%.

Dr. Tsai said that without increasing air resistance, the filtration efficiency of the electrostatic charged meltblown non-woven fabrics is 10 times higher than the non-charged fabrics. This technique allowsN95 users to be able to breathe easily. To enhance the overall performance, the new technology of hydraulic friction electrification invented in 2018 doubled the efficiency of the filter material. The original N95 mask consisted two layers of fabric, but the new technology only requires one layer, making the masks more breathable.

To date, over 80 products were commercialized using Tsai’s technology, including masks and surgical gowns, which has benefitted more than 1 billion of people's health. His achievement made him the only two times recipient of the "B. Otto and Kathleen Wheeley Award", a prestigious award established by University of Tennessee.

Persistent research to help counter the pandemic

Dr. Tsai, a 68-year-old former professor who served at University of Tennessee for more than 35 years, continues with his research well into his retirement. With the ongoing spread of Covid-19 in the United States, Dr. Tsai has spent majority of time conducting experiments and exploring different ways to disinfect face masks for reusing. In April, he published an article proposing a variety of methods to clean and reuse N95 mask without compromising the filter performance. After the United States reopened its economy, the number of confirmed cases in many states continue to increase. Having serious concern over the rising numbers, Dr. Tsai worked to increase the production of N95 masks, and continued to optimize the materials that are used to make protective clothing and medical masks.

Dr. Tsai pointed out that although N95 is able to filter 95% of airborne particles, the air is also blocked with minimal airflow, causing the issue of discomfort from users and medical workers. To counter such problem, he developed a new material technology by increasing the breathability from 15% to 18% ~19%. The improvement is expected to benefit more medical personnel working on the frontline.

From a country boy to an outstanding scientist

Dr. Peter Tsai’s indissoluble bond with masks came from his educational foundation in Taiwan. During the heyday of Taiwan’s textile industry in the 70s, Tsai, who grew up in the countryside, attended Taipei Institute of Technology (present day National Taipei University of Technology) and studied chemical fiber program in the Department of Fiber Engineering. After graduation, he started working in the textile industry. With the increasing feeling of lack of technical understandings behind his work, he used his entire saving to buy a one-way ticket to further his scientific study in the United States.

At that time, the country boy who intended to learn only a marketable skill in Taiwan did not expect that he would further his academic career in a foreign country. He integrated not only different knowledge such as fluid mechanics, electricity and materials science, but also used computer programs to calculate research results. After graduating from his research program, Dr. Tsai worked at University of Tennessee as a research scholar and successfully led the R&D team to develop the two core technologies of N95 mask. Having to achieve groundbreaking findings, however, he humbly said that "I am not a top scientist in Taiwan, my invention was only promoted onto the world stage because of the pandemic!" With his experience, Dr. Tsai encourages young students to strive on the road of scientific research. He believes that “to achieve innovative scientific research results, one must master the integration of knowledge, practical and critical thinking skills.”