Interfacial Stereocomplexation of Electroactive Poly(lactic acid)Nanofibrous Membranes for Efficient Filtration of Airborne PMs

Poly(lactic acid) membrane has great potential in the field of biodegradable air filtration materials, but the low proportion of electroactive phase leads to weak dielectric properties of the membrane, making it difficult to meet the requirements for capturing of high-performance filter materials for airborne particulate matters(PMs). Herein, the stereocomplex(SC) composed of poly(L-lactic acid)(PLLA) and poly(D-lactic acid)(PDLA) was employed to provide the proportion of high electroactive phase formation, and the stereocomplexed interface of electroactive poly(lactic acid) nanofiber membrane was established by coaxial electrospinning strategy. By adjusting the injection speed during spinning, fiber morphology and the formation of carbonyl(C=O) dipole, beta crystal phase and interfacial stereocomplex crystals(SCs), the nanofiber membrane of core-shell(CS) structure obtained has improved surface potential(9.3 kV) and dielectric constant of 1.60. The mechanical properties of the composite fiber membrane with interfacial stereocomplex were significantly improved. The tensile strength and Young's modulus of core-shell 1.5(CS1.5) nanofiber membrane reached 17.2 MPa and 351.1 MPa, respectively, which were obviously superior to the pure PLLA membrane. More importantly, the enhanced electrical activity significantly enhanced the filtration efficiency of poly(lactic acid) nanofiber membranes for PM0.3 and PM2.5, and the stereocomplexed interface had a unique advantage in dealing with dust collection at high flow rate. The filtration efficiency of CS1.5 nanofiber membrane increased from 82.5% at 10 L/min to 97.9% at 85 L/min. Furthermore, we developed the strategy of using interfacial stereocomplex to stimulate the electroactivity of poly(lactic acid) for the first time, providing valuable insights for solving the application bottleneck of poly(lactic acid) membrane filtration materials.