Green electrospinning fully bio-based lightweight nanofibrous membrane for high-performance and antibacterial air filtration via small molecule mutual support mechanism

Functionalization and lightweighting of high-performance air filters can markedly improve quality of life. However, achieving this goal with green processes and fully bio-based materials remains challenging, placing significant strain on the environment and energy resources. The key lies in mastering the appropriate material matching strategy and its mechanism for the forming of membrane structure. Here, ethyl cellulose (EC) / tea polyphenol (TP) / betaine (BT) bimodal nanofibrous membranes were fabricated by blended electrospinning using green solvents. The synergistic interaction between TP and BT termed the "small molecule mutual support mechanism", is particularly compelling. TP could prevent polymer chains from being difficult to deform because of BT, making it good spinnable even under high BT loading. In this case, the cations of BT were sufficient to cause jet splitting, forming a bimodal structure. Consequently, high-performance antibacterial air filtration had been achieved under ultra-light and ultra-thin conditions (15% and 8% of N95 masks, respectively). The filtration efficiency for 0.3 μm NaCl particles, pressure drop, and quality factor were 99.79%, 58.7 Pa, and 0.1050 Pa^-1, respectively. The antibacterial rates for Escherichia coli and Staphylococcus aureus were all 99.99%. This study offers insights into the green and sustainable design of advanced protective equipment.