Superiority of Electrospun Nanofibers in Face Masks

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Due to the ongoing COVID-19 pandemic, we’ve all been forced to implement changes to our daily lives, with one major adjustment being the need to wear face masks when out in public. It’s important to decipher what the most effective yet sustainable options may be for face masks moving forward.

With the pandemic raging on and overall awareness toward personal protection growing, we are seeing increased demand in the market for disposable face masks, which is expected to continue growing over the next decade. Our current situation, however, has proven the need for reusable masks as opposed to the single-use, disposable masks that are more tenable in the short term.

First, let’s discuss the current market for face masks. A major function of these protective devices is the filtration of airborne particulate pollutants by nanofibers or microfibers. Traditionally, melt blowing has been a successful and low-cost process for production of these filtration microfibers.

However, many are now making the case for electrospun (ES) nanofibers when used as an active layer in face masks. ES nanofibers are 10-100 times smaller than the conventional melt-blown (MB) microfibers, allowing for increased protection against air particles, bacteria, and viruses like COVID-19. Not only does it provide better protection and filtration efficiency, but the electrospun nanofibers are also responsible for increasing the user's breathability. Additionally, recent technological advancements have allowed for nanofibres to be produced in large volumes at a cost low enough to compete with the existing melt-blown alternative.

Keeping in mind the need for masks to be both effective and environmentally friendly, researchers conducted a study on the reusability effectiveness of MB and ES nanofiber filters after going through a cleaning process where the filters were both sprayed and dipped with ethanol.

Results showed that the melt-blown filters are best utilized in single-use applications, as researchers noted a steep reduction in the filtration mechanics ability after ethanol cleaning. This is because the cleaning process causes the MB filter to lose its electrostatic charge, which is responsible for the sharp drop in its performance abilities.

The study also showed that electrospun nanofibers, which have a high surface area per unit mass and are highly water resistant, can be successfully reused multiple times without losing any filtration efficiency even after being dosed with ethanol. These results proved that the reusable nature of ES nanofibres in comparison to MB filters makes them superior to melt-blown filtration.