Sustainable trans-scale fibrous membranes for stable ultra-protective air filtration

Disposable fibrous air filtration media represent one of the most convenient and effective approaches for personal health protection. Nevertheless, restricted by the technical bottlenecks of spinning technologies in fabricating ultrafine nanofibers and designing topological filtration networks, current filters cannot realize reliable ultra-protection against ultrafine particulate matter (PM). Moreover, non-degradable waste from excessive filter use imposes severe environmental burdens. Herein, we report a universal multi-level splitting electrospinning strategy for fabricating a variety of biodegradable trans-scale fiber membranes (TSFM). The hierarchical interweaving and stacking of ultrafine nanofibers, nanofibers, and submicron fibers endow the lightweight TSFM with tortuous interception networks and abundant mass and energy transport channels. Consequently, they can achieve a stable ultra-efficient PM_0.3 removal, low air resistance, great breathability, and reduce polymer consumption by 99% relative to commercial N95 respirators. This work may boost the iterative upgrading of advanced spinning technologies and the development of high-performance, sustainable filtration and separation materials.