ABSTRACT
Nanofibers have potential applications as filters for particles with diameters <10 µm owing to their large specific surface area, macropores, and controllable geometry or diameter. The filtration efficiency can be increased by creating nanonets (<50 nm) whose diameter is smaller than that of nanofibers. This study investigates the effect of process conditions on the generation of nanonet structures from a polyacrylonitrile (PAN) solution containing cation surfactants; in addition, the filtration performance is analyzed. The applied electrospinning voltage and the electrostatic treatment of meltblown polypropylene (used as a substrate) are the most influential process parameters of nanonet formation. Electrospun polyacrylonitrile-cetylmethylammonium bromide (PAN-CTAB) showed a nanofiber/nanonet structure and improved thermal and mechanical properties compared with those of the electrospun PAN. The pore size distribution and filter efficiency of the PAN nanofiber web and PAN-CTAB nanofiber/nanonet web with meltblown were measured. The resulting PAN-CTAB nanofiber/nanonet air filter showed a high filtration efficiency of 99% and a low pressure drop of 7.7 mmH2O at an air flow rate of 80 L/min. The process control methods for the nanonet structures studied herein provide a new approach for developing functional materials for air-filtration applications.
