The coronavirus disease 2019 pandemic has led to a major shortage of N95 respirators, which are essential for protecting healthcare professionals and the general public who may come into contact with the virus. Thus, it is essential to determine how we can reuse respirators and other personal protective equipment in these urgent times. We investigated multiple commonly used disinfection schemes on media with particle filtration efficiency of 95%. Heating was recently found to inactivate the virus in solution within 5 min at 70°C and is among the most scalable, user-friendly methods for viral disinfection. We found that heat (≤85°C) under various humidities (≤100% relative humidity, RH) was the most promising, nondestructive method for the preservation of filtration properties in meltblown fabrics as well as N95-grade respirators. At 85°C, 30% RH, we were able to perform 50 cycles of heat treatment without significant changes in the filtration efficiency. At low humidity or dry conditions, temperatures up to 100°C were not found to alter the filtration efficiency significantly within 20 cycles of treatment. Ultraviolet (UV) irradiation was a secondary choice, which was able to withstand 10 cycles of treatment and showed small degradation by 20 cycles. However, UV can potentially impact the material strength and subsequent sealing of respirators. Finally, treatments involving liquids and vapors require caution, as steam, alcohol, and household bleach all may lead to degradation of the filtration efficiency, leaving the user vulnerable to the viral aerosols.

The COVID-19 pandemic is currently causing a severe disruption and shortage in the global supply chain of necessary personal protective equipment (e.g., N95 respirators). The U.S. CDC has recommended use of household cloth by the general public to make cloth face coverings as a method of source control. We evaluated the filtration properties of natural and synthetic materials using a modified procedure for N95 respirator approval. Common fabrics of cotton, polyester, nylon, and silk had filtration efficiency of 5–25%, polypropylene spunbond had filtration efficiency 6–10%, and paper-based products had filtration efficiency of 10–20%. An advantage of polypropylene spunbond is that it can be simply triboelectrically charged to enhance the filtration efficiency (from 6 to >10%) without any increase in pressure (stable overnight and in humid environments). Using the filtration quality factor, fabric microstructure, and charging ability, we are able to provide an assessment of suggested fabric materials for homemade facial coverings.

Capacitance loss with the increase of mass loading represents an outstanding challenge for supercapacitors. Here we demonstrate for the first time a mm-thick, 3D printed graphene aerogel structure that can support pseudocapacitive MnO 2 to hundreds of mg/cm 2 without sacrificing its gravimetric and volumetric performance. The electrode simultaneously achieves high gravimetric, areal, and volumetric capacitances, which is impossible for conventional bulk electrodes. Most importantly, these findings validate the new concept of ''printing'' practically feasible pseudocapacitor electrodes and devices.

The Coronavirus Disease 2019 pandemic has led to a major shortage of N95 respirators, which are essential to protecting healthcare professionals and the general public who may come into contact with the virus. Thus, it is essential to determine how we can reuse respirators and other personal protection in these urgent times. We investigated multiple commonly used and easily deployable, scalable disinfection schemes on media with particle filtration efficiency of 95%. Among these, heating (≤85 °C) under various humidities (≤100% RH) was the most promising, nondestructive method for the preservation of filtration properties in meltblown fabrics as well as N95-grade respirators. Heating can be applied up to 50 cycles (85 °C, 30% RH) without observation in the degradation of meltblown filtration performance. Ultraviolet (UV) irradiation was a secondary choice which was able to withstand 10 cycles of treatment and showed small degradation by 20 cycles. However, UV can also potentially impact the material strength and fit of respirators. Finally, treatments involving liquids and vapors require caution, as steam, alcohol, and household bleach may all lead to degradation of the filtration efficiency, leaving the user vulnerable to the viral aerosols.

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a pandemic globally. 1 As of 18 April, it had infected over 2 million people worldwide. Recently, a study reported that the median duration of SARS-CoV-2 RNA shedding in 113 patients was 17 days from symptom onset in Zhejiang and Shenzhen centers. 2 In Wuhan, where the coronavirus disease 2019 (COVID-19) first started, the duration of the infection