Electroactive, Antibacterial, and Biodegradable Poly(lactic acid) Nanofibrous Air Filters for Healthcare

Poly(lactic acid) (PLA)-based nanofibrous membranes (NFMs)holdgreat potential in the field of biodegradable filters for air purificationbut are largely limited by the relatively low electret propertiesand high susceptibility to bacteria. Herein, we disclosed a facileapproach to the fabrication of electroactive and antibacterial PLANFMs impregnated with a highly dielectric photocatalyst. In particular,the microwave-assisted doping (MAD) protocol was employed to yieldZn-doped titanium dioxide (Zn-TIO), featuring the well-defined anatasephase, a uniform size of & SIM;65 nm, and decreased band gap (3.0eV). The incorporation of Zn-TIO (2, 6, and 10 wt %) into PLA gaverise to a significant refinement of the electrospun nanofibers, decreasingfrom the highest diameter of 581 nm for pure PLA to the lowest valueof 264 nm. More importantly, dramatical improvements in the dielectricconstants, surface potential, and electret properties were simultaneouslyachieved for the composite NFMs, as exemplified by a nearly 94% increasein surface potential for 3-day-aged PLA/Zn-TIO (90/10) compared withthat of pure PLA. The well regulation of morphological features andpromotion of electroactivity contributed to a distinct increase inthe air filtration performance, as demonstrated by 98.7% filtrationof PM0.3 with the highest quality factor of 0.032 Pa-1 at the airflow velocity of 32 L/min for PLA/Zn-TIO(94/6), largely surpassing pure PLA (89.4%, 0.011 Pa-1). Benefiting from the effective generation of reactive radicalsand gradual release of Zn2+ by Zn-TIO, the electroactivePLA NFMs were ready to profoundly inactivate Escherichiacoli and Staphylococcus epidermidis. The exceptional combination of remarkable electret properties andexcellent antibacterial performance makes the PLA membrane filterspromising for healthcare.