Nanopatterned Electroactive Polylactic Acid Nanofibrous MOFilters for Efficient PM_0.3 Filtration and Bacterial Inhibition

Abstract

Biodegradable polylactic acid (PLA) nanofibrous membranes (NFMs) hold great potential to address the increasing airborne particulate matter (PM) and dramatic accumulation of plastic/microplastic pollution. However, the field of PLA NFM-based filters is still in its infancy, frequently dwarfed by the bottlenecks regarding relatively low surface activity, poor electroactivity, and insufficient PM capturing mechanisms. This effort discloses a microwave-assisted approach to minute-level synthesis of dielectric ZIF-8 nanocrystals with high specific surface area (over 1012 m2/g) and ultrasmall size (∼240 nm), which were intimately anchored onto PLA nanofibers (PLA@ZIF-8) by a combined “electrospinning–electrospray” strategy. This endowed the PLA@ZIF-8 NFMs with largely increased electroactivity in terms of elevated dielectric coefficient (an increase of 202%), surface potential (up to 5.8 kV), and triboelectric properties (output voltage of 30.8 V at 10 N, 0.5 Hz). Given the profound control over morphology and electroactivity, the PLA@ZIF-8 NFMs exhibited efficient filtration of PM0.3 (97.1%, 85 L/min) with a decreased air resistance (592.5 Pa), surpassing that of the pure PLA counterpart (88.4%, 650.9 Pa). This was essentially ascribed to realization of multiple filtration mechanisms for PLA@ZIF-8 NFMs, including enhanced physical interception, polar interactions, and electrostatic adsorption, and the unique self-charging function triggered by airflow vibrations. Moreover, perfect antibacterial performance was achieved for PLA@ZIF-8, showing ultrahigh inhibition rates of 99.9 and 100% against E. coli and S. aureus, respectively. The proposed hierarchical structuring strategy, offering the multifunction integration unattainable with conventional methods, may facilitate the development of biodegradable long-term air filters.

Extreme Orientation of Stereocomplexed Poly(lactic acid) Induced Ultrafine Electroactive Nanofibers for Respiratory Healthcare and Intelligent Diagnosis

“…Moreover, as shown in Figure S6, the removal efficiencies of the OSC-PLA NFMs for each PMs (particle size from 12 to 205 nm) were relatively high and stable compared with pure PLLA, especially at high airflow capacity. This is because the highly electroactive OSC-PLA NFMs with a high dielectric constant and surface potential revealed excellent charge storage capacity, which demonstrated strong electrostatic trapping capability . Furthermore, this was also confirmed by the excellent removal efficiencies of the OSC-PLA NFMs for PM 2.5 (Figures i and S7).…”

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.…”

Multi-Protection from Microbial and PM Pollutants by Humidity-Resistant, Breathable and Self-Charging Nanofibrous Membranes

“…Many endeavors have been made to address these disadvantages, such as incorporation of functional dielectrics, and utilization of modified electrospinning to refine the fiber and to facilitate the alignment of PLA fibers. ,− More importantly, by exploiting the stereocomplexation between PLLA and PDLA, we have demonstrated the facilitated evolution from the 10 3 -helix conformation to the 3 1 -helix conformation, promoting the hydrogen bonding density and thus the polarity and electroactivity of PLA fibers . Remarkably, the utilization of increased dielectric performance would further improve the electroactivity of PLA air filters.…”