Highly efficient, low-resistant, well-ordered PAN nanofiber membranes for air filtration

Disordered pore structures present in traditional fiber filtration materials often mean they are incapable of simultaneously achieving high filtration efficiencies and low air resistance. In this study, the excellent spinnability, hydrophobicity, and stability properties of polyacrylonitrile (PAN) have been exploited to prepare electrospun nanofiber membranes containing well-ordered fibers with diameters ranging from 240 to 404 nm and pore sizes ranging from 1.91 to 6.45 µm. These nanofiber membranes exhibit excellent air filtration efficiencies ranging from 94.83 % to 99.60 % for aerosol particles with diameters of around 300 nm, which occurs with a corresponding pressure drop from 33 to 98 Pa. Three-dimensional (3D) models of disordered nanofiber membranes, standard-ordered nanofiber membranes, and cross-ordered nanofiber membranes were constructed, which confirm that the ordered structure can greatly reduce the pressure drop of the fiber membranes whilst maintaining filtration efficiency. The new well-ordered membranes exhibit significantly higher filtration efficiencies and lower air resistance than traditional fiber air membranes that contain a more disordered structure, meaning they should be well-suited for air-filtration applications.