Morphological Manipulation of Highly Electroactive Poly(lactic acid) Nanofibrous Membranes for Efficient Removal of Airborne PM_0.3

The surface functionalization of poly(lactic acid)(PLA)nanofibers was carried out by electrospraying zeolite imidazolium framework-8(ZIF-8)dispersion to enhance the surface charge capture and storage capacity of PLA/ZIF-8 nanofibrous membranes(NFMs), thus improving the electrostatic adsorption effect and filtration performance. By adding different contents of ZIF-8 to the dispersion to regulate the load of ZIF-8 anchored to the fiber surface,the relationship between the content of ZIF-8 and the evolution of the NFMs morphology and properties was explored. Scanning electron microscopy(SEM) was used to characterize the microstructure of the NFMs,and the chemical properties,interface interaction and crystal structure evolution mechanism were analyzed by Fourier trans. form infrared spectroscopy(FTIR)and X-ray diffraction XRD analyses. To characterize the electroactivity and tribo. electric output performance of the membranes,the surface potential,dielectric constant and open-circuit voltage were evaluated by electrostatic tester,dielectric tester and electrometer,respectively. The mechanical properties of PLA/ZIF-8 NFMs were tested by universal testing machine,and a homemade air filtration test platform was used to explore the high-efficiency filtration mechanisms of the membranes. The results showed that the PLA/ZIF-8 NFMs had high electrical activity,high filtration efficiency,low air resistance,and excellent mechanical properties. The surface potential and maximum open-circuit voltage of the NFMs reached 5.9 kV and 30.9 V,which were 5.6 times and 5.3 times higher than those of the comparative samples,Pure PLA,respectively. Meanwhile,the tensile strength and tensile toughness were increased by 78% and 111%,respectively. More importantly,the PM0.3 filtration perfor. mance of PLA/ZIF-8 NFMs was greatly improved(up to 12.6% increase),and the air resistance was reduced(40 Pa, 65 L/min). The proposed environmentally friendly PLA/ZIF-8 NFMs have broad application prospects in the fields of filtering ultrafine particles and blocking the transmission of viral aerosols.