Rechargeable polyamide-based N-halamine nanofibrous membranes for renewable, high-efficiency, and antibacterial respirators

Emerging infectious diseases (EIDs) have been acknowledged as a major public health concern worldwide. Unfortunately, most protective respirators used to prevent EID transmission suffer from the disadvantage of lacking antimicrobial activity, leading to an increased risk of cross-contamination and post-infection. Herein, we report a novel and facile strategy to fabricate rechargeable and biocidal air filtration materials by creating advanced N-halamine structures based on electrospun polyamide (PA) nanofibers. Our approach can endow the resultant nanofibrous membranes with powerful biocidal activity (6 log CFU reduction against E. coli), an ultrahigh fine particle capture efficiency of 99.999% (N100 level for masks), and can allow the antibacterial efficacy and air filtration performance to be renewed in a one-step chlorination process, which has never been reported before. More importantly, for the first time, we revealed the synergistic effect involving the intrinsic structure of polymers and the assembling structure of nanofibers on the chlorination capacity. The successful fabrication of such a fascinating membrane can provide new insights into the development of nanofibrous materials in a multifunctional, durable, and renewable form.