Plasmonic and Superhydrophobic Self-Decontaminating N95 Respirators

Abstract

The COVID-19 pandemic is endangering the world due to the spread of respiration droplets with viruses. Medical workers and frontline staff need to wear respirators to protect themselves from breathing in the virus-containing respiration droplets. The most frequently used state-of-the-art respirators are of N95 standard; however, they lack selfdecontamination capabilities. In addition, the viruses and bacteria can accumulate on the respirator surfaces, possessing high risks to the wearers over long-term usage. Photothermal decontamination is a contactless, fast, low-cost, and widely available method, capable of decontaminating the respirators. Herein, we report a plasmonic photothermal and superhydrophobic coating on N95 respirators, possessing significantly better protection than existing personal protection equipment. The plasmonic heating can raise the surface temperature to over 80 °C for this type of respirator within 1 min of sunlight illumination. The superhydrophobic features prohibit respiration droplets from accumulating on the respirator surfaces. The presence of the silver nanoparticles can provide additional protection via the silver ion's disinfection toward microbes. These synergistic features of the composite coatings provide the N95 respirator with better protection and can inspire experts from interdisciplinary fields to develop better personal protection equipment to fight the COVID-19 pandemic.

A technical review of face mask wearing in preventing respiratory COVID-19 transmission

“…The sterilization techniques developed by Kumar and colleagues [ 51 ] could help decontaminate N95 respirators via autoclave treatment, ethylene oxide gas, low-temperature hydrogen peroxide gas plasma treatment, vaporous hydrogen peroxide exposure, and peracetic acid dry fogging without damaging their shape, delicate structure, and material properties so that they can replicate their performance as when they are brand new. For the decontamination of N95 respirators over long-term usage and the removal of accumulated viruses and bacteria on the respirator surfaces, a new mask capable of photothermal decontamination was also designed [ 52∗ ] by applying a plasmonic and superhydrophobic coating on the surface of N95 respirators, offering significantly better protection. In a similar design strategy, the same team has developed a reusable and recyclable graphene mask that can self-sterilize under sunlight illumination [ 53 ].…”

Advances in Facemasks during the COVID-19 Pandemic Era

“…Right, FESEM image of the sample after 100 cycles of laser decontamination. Reproduced with permission from ref ( 144 ). Copyright 2020 American Chemical Society.…”

“…Plasmonic photothermal decontamination was studied using solar energy (600 W/m 2 ), which resulted in a 60 °C increase in temperature; such a high temperature sufficiently inactivated SARS-CoV-2 ( Figure 6 c). 144 Due to their photothermal properties, graphene-coated masks have also been used to sterilize viruses that can potentially remain on the facemask surface. Graphene-coated masks demonstrated excellent absorption (>95%) across the entire solar spectrum (300–2500 nm).…”

Superhydrophobic, photo-sterilize, and reusable mask based on graphene nanosheet-embedded carbon (GNEC) film

“…The mask is based on graphene nanosheetembedded carbon (GNEC) film and developed by ultrasonicextrusion, to provide protection against the COVID-19. In hydrophobicity and photothermal properties, GNEC masks show better performance (water contact angle: 157.9°, temperature: 110 °C) than laser-induced graphene (silver nanoparticles) coatings (water contact angle: 140°, temperature: ~ 90 °C) [22]. nanostructure in smooth fibers (polypropylene, chemical structural formula: -[CH2-CH(CH)3]n-).…”