Fabrication of ε-Poly-L-lysine (ε-PL) modified electrospun antibacterial nanofibrous membranes for PM1.0 filtration

Segregating airborne particulate matters (PMs, especially PM1.0) with high transmissibility of bacterial and viral pathogens is crucial for ensuring outdoor breathing safety. Electrospun nanofiber membranes (ENMs) have shown great promise for this purpose. However, the application of traditional ENMs is usually plagued by bacterial growth causing severe public health concern. Although some research has been done to overcome this challenge by doping antibacterial materials, the potential negative effects of these materials on the human body cannot be ignored. In this study, the ε-Poly-L-lysine (ε-PL), a green broad-spectrum antibacterial reagent, was grafted onto the surface of polydopamine (PDA) coated polyacrylonitrile (PAN) ENM via addition of Schiff base and Michael reaction. Experimental results indicated that the introduction of the ε-PL is key to the antibacterial performance of the membranes, and the antibacterial efficacy of E. coli and B. subtilis can reach to 99.86 % and 99.99 % respectively. Even after 7 days, the antibacterial efficiency of membrane remained at a high level. Additionally, the uniform structure of membranes endowed it with a high filtration efficiency of 80.9 % for PM1.0 particles with a moderate transmembrane pressure drop (TMP) of 250 Pa and the corresponding quality factor is approximately 0.0066 Pa−1. This study has far-reaching implications for the design of green antibacterial nanofibrous membranes to realize the segregation of harmful PMs.