Electroactive PLA/ZnO@PDA nanofibrous membranes for high performance ultrafine particulate matter filtration

Electrospun poly(lactic acid) (PLA) fibrous filter membranes face the bottleneck problem of the weak polarization ability under electric field and low charge storage stability of PLA. Therefore, high surface-active PDA-coated ZnO (ZnO@PDA) nanodielectrics were anchored to the surface of PLA nanofibers by electrospinning-elctrospray technology (PLA/ZP) to enhance the electret performance and triboelectric effect of PLA nanofibrous membranes, thereby realizing electrostatic capturing and long-lasting filtration. The surface morphology and molecular structure of PLA/ZnO@PDA (PLA/ZP) nanofibrous membranes were characterized to explore the relationship among the interfacial interactions between ZnO@PDA and PLA, and the electroactivity, filtration performance, charge regeneration mechanism, and respiration monitoring capability of PLA/ZP nanofibrous membranes. The results showed that the PLA/ZP nanofibrous membrane had high electroactivity and excellent air filtration performance, and its surface potential and dielectric properties were 2.9 and 1.65 times higher than those of pure PLA nanofibrous membrane, respectively. At a high air flow rate of 85 L/min, the PLA/ZP nanofibrous membrane still maintained 98.82% of PM_0.3 filtration efficiency and 301.3 Pa of pressure drop. Benefiting from the improved electroactivity and increased specific surface area, the output voltage of the PLA/ZP nanofibrous membrane achieved 11.5 V (10 N, 0.5 Hz), which was much higher than that of the pure PLA nanofibrous membrane (1.56 V), and integrating it into respiratory masks enabled real-time monitoring of respiration. The proposed PLA/ZP nanofibrous membrane holds a promising application in the fields of long-lasting particle capture and human health monitoring.