“…11,19,20 Nowadays, a variety of polymers are used to prepare nanofiber air filtration membrane by electrospinning technology, for example, polyacrylonitrile (PAN), polyamine ester (PU), polylactic acid (PA), polyvinyl alcohol (PVA), polyvinylidene fluoride (PVDF), etc. [21][22] PAN is an amorphous vinyl-type polymer that contains a cyano group in each repeat unit. It has smaller dielectric loss and higher thermal stability that allow it to be widely used as carbon fiber precursors.…”