Daylight-driven rechargeable antibacterial and antiviral nanofibrous membranes for bioprotective applications

Si, Yang; Zhang, Zheng; Wu, Wanrong; Fu, Qiuxia; Huang, Kang; Nitin, Nitin; Ding, Bin; Sun, Gang

With the above results in mind, we further demonstrated the utilization of BDCA-RNM as a biocidal surface function layer for bioprotection applications. To facilely integrate it to current PPE materials, we investigated the interception properties of the BDCA-RNM against ultrafine particles. We carried out the filtration performance evaluation by using the polydisperse sodium chloride (NaCl) particles with a diam-eter of 300 to 500 nm under increasing airflow. As shown in Fig. 5A , by increasing the airflow from 10 to 90 liter min −1 , the filtration efficiency of the BDCA-RNMs exhibited a very slight decrease from 99.98 to 99.07%, which was distinctly higher than that of the N95 facial mask (95%), widely used by HCWs. Meanwhile, the pressure drops showed an increased trend directly proportional to the airflow, indicating a cellular-dominated permeation behavior similar to that of the open-cell porous structure (51) . Significantly, the maximum pressure drop of the BDCA-RNM was 128 Pa at 90 liter min −1 , which was only a third of the pressure drop standard of the N95 facemask (350 Pa at 85 liter min −1 ) (8), highlighting the robust breathability of the nanofibrous structure. The promising filtration efficiency was also confirmed by SEM observations; from Fig. 5B , we can see that abundant particles were captured on the top surface of the BDCA-RNM, whereas no particles were observed on the bottom surface, and the membranes also well maintain their structural integrity during the filtration process with high airflow. To further visually evaluate the filtration capacity, we estimated the filtration quality factor (QF) of BDCA-RNM with different basis weight (Fig. 5C) . The BDCA-RNM with 1 / 10 of the basis weight exhibited the comparable QF values with current commercialized filtration materials, indicating the promising potential for protective applications (51, 52) .