Hierarchical dual-nanonet of polymer nanofibers and supramolecular nanofibrils for air filtration with a high filtration efficiency, low air resistance and high moisture permeation

Abstract

Air pollution and public health incidents have become a serious global concern. Hierarchical nanofibrous membranes are considered as high-performance filters with an advanced structure, but their reliable fabrication is still challenging. Herein, a novel methodology involving the combination of a multi-orifices solution blowing technique process and low molecule organogel self-assembly strategy is reported to construct a hierarchical dual-nanonet of polymer nanofibers and supramolecular nanofibrils. Through an adsorption–nucleation–growth model, ultrathin supramolecular nanofibrils (10–30 nm) were assembled in situ within a fluffy solution-blown nanofiber mat with strong inter-fiber connections. Benefiting from the synergistic effects of the ultrathin diameter, small pore size, high porosity and stable inter-fiber connections, the hierarchical dual-nanonet demonstrates robust mechanical strength, a high filtration efficiency (99.999% for 0.3 μm), low pressure drop (32 Pa), a high quality factor (0.189 Pa⁻¹), and a boosted moisture permeation. The comprehensive performances indicate promising applications in various filtration applications, especially in the field of personal protective equipment.