One-step fabrication of polylactic acid (PLA) nanofibrous membranes with spider-web-like structure for...

High-efficiency air filters are in high demand to protect human health from the threat of ultrafine particulate matters (PM). However, most commercial air filters are less effective for PM_0.3 capture and/or still suffer from undesirable pressure drops. They are also typically petroleum-based. Herein, a double-jet synchronous electrospinning technology was demonstrated to fabricate spider-web-like polylactic acid (PLA) nanofibrous membranes (SPNM) in one step. The properties of spinning solutions were regulated to construct favorable multi-scale nanofiber and bead structures that mimicked the structural units in spider-webs. The as-prepared SPNM exhibited excellent filtration efficiency (99.87 %) and high quality factor (0.321 Pa^-1) against the PM_0.3, while presenting an attractively low pressure drop (19 Pa). Additionally, the filtration performance of SPNM was almost completely preserved during 10-cycle tests and the 6-month long-term tests, showing excellent function stability and durability. Benefiting from its good hydrophobicity (WCA = 143.2°), SPNM also presented a satisfactory filtration efficiency (>99.37 %) with low pressure drop (18 Pa) at an environment with humidity at 90 % against PM_0.3. Furthermore, the unique structure increased the mechanical strength of SPNM, facilitating the processability for practical applications. Overall, this work may shed light on a promising approach for developing biomass-based, highly efficient filtration materials with hierarchical structures.