High-Performance PM0.3 Air Filters Using Self-Polarized Electret Nanofiber/Nets

Particulate matter (PM) pollution in air is thought to be an important mortality risk factor globally. Most existing air filters face the extreme challenge of effectively removing PM 0.3 , which has the most penetration particle size (MPPS) of ≈0.3 µm yet is particularly harmful. Here, an innovative in situ electret electrospinning/netting technique that can manipulate both solution phase separation and crystal phase transition is reported to develop self-polarized polyvinylidene fluoride nanofiber/net membranes with 2D networks and superior surface adhesion. By combining the true nanoscale diameter (≈21 nm), small pore size (≈0.26 µm), and highly electret surface (6.8 kV potential) of the 2D nanonets, the synergistic effect of sieving and adhesion for MPPS PM 0.3 is achieved. Such double capture characteristic enables the high-efficiency (≈99.998%) capture of PM 0.3 while maintaining low air resistance (≈0.1% atmosphere pressure). Moreover, the nanofiber/net filters show integrated properties of superhydrophobicity, desirable transparency (91%), and long-term stability. The synthesis of such attractive nanomaterials presents a promising attempt toward the development of high-performance filtration/separation materials for numerous applications.