ABSTRACT
Recently, the worldwide demand for disposable masks has increased due to COVID-19 infections and severe air pollution. Personal masks should reduce breathe resistance while maintaining filtering performance. In this study, a solution blowing process is used to produce composite nanofiber filters to co-spin two polymers at once. The manufacture process of the various fiber diameter filter was designed, and the filtration performance and differential pressure of the prepared filter was investigated. Poly vinylidene fluoride-hexafluoropropylene (PVDF-HFP) and Polylactic acid (PLA) fibers were chosen to be entangled together in a layer with a diameter of 1.05 mu m and 0.33 mu m. Composite nanofilters showed up to 87% filtration efficiency and 32 Pa differential pressure.
ABSTRACT
A broad-spectrum antimicrobial respiration apparatus designed to fight bacteria, viruses, fungi, and other biological agents is critical in halting the current pandemic's trajectory and containing future outbreaks. We applied a simple and effective electrodeposition method for metal (copper, silver, and zinc) coating the surface of halloysite nanotubes (HNTs). These nanoparticles are known to possess potent antiviral and antimicrobial properties. Metal-coated HNTs (mHNTs) were then added to polylactic acid (PLA) and extruded to form an mHNT/PLA 3D composite printer filament. Our composite 3D printer filament was then used to fabricate an N95-style mask with an interchangeable/replaceable filter with surfaces designed to inactivate a virus and kill bacteria on contact, thus reducing deadly infections. The filter, made of a multilayered antimicrobial/mHNT blow spun polymer and fabric, is disposable, while the mask can be sanitized and reused. We used several in vitro means of assessing critical clinical features and assessed the bacterial growth inhibition against commonly encountered bacterial strains. These tests demonstrated the capability of our antimicrobial filament to fabricate N95 masks and filters that possessed antibacterial capabilities against both Gram-negative and Gram-positive bacteria.
ABSTRACT
The demand for air filtration products has increased significantly with the aggravation of air pollution and the pandemic of coronavirus disease (COVID-19). It is urgently needed to develop an air filtration membrane that exhibits lasting filtration performance and antibacterial activity. Herein, we report a large-scale blow spinning technique to produce polyvinylidene fluoride (PVDF) nanofiber membranes for highly efficient air mechanical filtration and its antibacterial modification by adding the silver nanoparticles (AgNPs). The PVDF nanofiber membrane with an area density of only 1.0 g/m2 exhibits the highest filtration efficiency of 98.63% for the particle with a size of 0.3 μm. After eliminating static electricity, there is almost no reduction in the filtration efficiency of particulate matter with a size larger than 1 μm and only 4.69% decrease in the particulate matter with a size of 0.5 μm. Hence, the PVDF nanofiber membrane with nanostructures for air filtration works mainly by the means of mechanical filtration. To inhibit the survival or growth of the intercepted bacteria on the membrane, the PVDF/AgNPs nanofiber membrane was fabricated by adding AgNPs to PVDF nanofibers, which exhibits the strongest antibacterial activity of more than 99% and an excellent filtration efficiency similar to that without adding AgNPs. The nanofiber membrane with antibacterial activity is expected to extend the service or storage time or be reused without loss of filtration performance. Additionally, large-scale production of nanofiber filtration membranes has been realized using a multi-needle blow spinning machine. © 2022 American Chemical Society.