Development of tree-like nanofibrous air filter with durable antibacterial property

[Display omitted] •The tree-like structure of AgNPs/PVDF nanofiber membrane was fabricated by electrospinning.•The AgNPs/PVDF nanofiber membrane with high filtration efficiency and low pressure drop.•The AgNPs/PVDF air filter with durable antibacterial activity against both for S. aureus and E. coli. High filtration performance and antibacterial property have been the main concerns of air filters. In this work, the silver nanoparticles (AgNPs) were produced by liquid phase reduction method and were added into polyvinylidene fluoride (PVDF) solutions at a ratio of 0.2%, 0.4%, 0.6%, 0.8%, and 1% for electrospinning. Nanofibers with the tree-like structure were fabricated by controlling the processing parameters. Therefore, a tree-like AgNPs/PVDF nanofiber membrane containing AgNPs was successfully developed. The AgNPs solutions were analyzed by UV–vis absorption spectrum to determine the size of AgNPs, and the nanofiber membranes were also evaluated in terms of morphology, structure, hydrophobic property, filtration performance, and antibacterial property. The results showed that the size of AgNPs was approximately 10 nm, the average diameters of branch-like fibers and stem-like fibers were about 30.8 nm and between 90 nm with 140 nm, respectively. The addition of AgNPs did not change the hydrophobic property of the PVDF nanofiber membrane; the filtration efficiency of AgNPs/PVDF nanofiber membrane was 99.95–99.97% and the lowest pressure drop was 137.5 Pa; the bacterial reduction rates (BR) value against for S. aureus and E. coli were kept at a level of higher than 99.6% after exposure to sunlight for two weeks. Therefore, a kind of air filter with high filtration performance and durable antibacterial property was successfully developed by adding AgNPs and by creating tree-like structure fibers.