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

Abstract

Poly(lactic acid) (PLA)-based nanofibrous membranes (NFMs) hold great potential in the field of biodegradable filters for air purification but are largely limited by the relatively low electret properties and high susceptibility to bacteria. Herein, we disclosed a facile approach to the fabrication of electroactive and antibacterial PLA NFMs impregnated with a highly dielectric photocatalyst. In particular, the microwave-assisted doping (MAD) protocol was employed to yield Zn-doped titanium dioxide (Zn-TIO), featuring the well-defined anatase phase, a uniform size of ∼65 nm, and decreased band gap (3.0 eV). The incorporation of Zn-TIO (2, 6, and 10 wt %) into PLA gave rise to a significant refinement of the electrospun nanofibers, decreasing from the highest diameter of 581 nm for pure PLA to the lowest value of 264 nm. More importantly, dramatical improvements in the dielectric constants, surface potential, and electret properties were simultaneously achieved for the composite NFMs, as exemplified by a nearly 94% increase in surface potential for 3-day-aged PLA/Zn-TIO (90/10) compared with that of pure PLA. The well regulation of morphological features and promotion of electroactivity contributed to a distinct increase in the air filtration performance, as demonstrated by 98.7% filtration of PM 0.3 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 radicals and gradual release of Zn 2+ by Zn-TIO, the electroactive PLA NFMs were ready to profoundly inactivate Escherichia coli and Staphylococcus epidermidis. The exceptional combination of remarkable electret properties and excellent antibacterial performance makes the PLA membrane filters promising for healthcare.

Biodegradable Electroactive Nanofibrous Air Filters for Long-Term Respiratory Healthcare and Self-Powered Monitoring

“…Since the filtration membranes are subjected to stretching during use, it is necessary for the PLA membranes to have proper mechanical properties, including strength, modulus, and toughness. , As revealed by the stress–strain curves in Figure S7a, it is apparent that all PLA FMs displayed similar deformation modes, and the mechanical response upon external deformation of PLA FMs was significantly promoted by our SREA strategy. As shown in Figure S7b,c, the Young’ s modulus and tensile strength of SP4000 gradually increased to 469.5 ± 2.5 and 19.5 ± 0.84 MPa (45 and 107% increase compared with those of SP300), respectively.…”

Autoclavable Nanofiber Laminated Fabrics with Waterproof and Breathability for Reusable Medical Protective Textiles

“…The filtration efficiency against 0.3 μm NaCl aerosol showed a slight increase and reached high equilibrium values of 99.7% (Figure d). With the increasing of membrane basis weight, the membrane thickness increased and the pore size decreased, therefore increasing the interception efficiency. − In addition, the tensile strength of the nanofibrous membrane also dramatically enhanced from 71.2 to 258.8 cN with increasing membrane basis weight (Figure S6a). Nevertheless, the increased basis weight of nanofiber layer slightly deteriorated the breathability.…”

Preparation of porous polylactic acid nanofibers and application in non-electret high-efficiency filtration composites

“…This was attributed to the porous structure of the nanofibers inducing an increase in the specific surface area and porosity, which were beneficial for reducing the pressure drop and improving the particle trapping ability. 8,31 …”

“…6,7 Furthermore, recent ndings have proved that viruses carried in PM 2.5 are one of the important potential causes of the worldwide outbreak of the COVID-19 pandemic. 4,[8][9][10] At present, emission reduction and passive ltration are the main effective solutions to alleviate the threats of and damage caused by particulate matter. 11 Therefore, lter materials for personal protection and indoor air purication that can effectively capture particulate matter, are in high demand in recent years.…”