Tea polyphenols-enhanced in-situ polarization of polyvinylidene fluoride nanofiber material with antibacterial and high-filtration, low-resistance filtering performances

Abstract

To address the issue of viral and bacterial contamination in air filtration materials, specifically focusing on the accumulation of viruses on aerogels and long-term bacterial growth, a hydrophobic and antimicrobial polyvinylidene fluoride (PVDF)/tea polyphenols (TPs) nanofibers membrane was prepared by electrospinning technique with natural antimicrobial TPs and ferroelectric PVDF as raw materials. By scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and testing on contact angle and antimicrobial properties, the performances of the nanofiber membranes were characterized. It was verified by XRD and FTIR analyses that the TPs facilitated the transition of PVDF from α-crystalline phase to the β-crystalline phase, thereby enhancing the polarization effect of PVDF nanofiber membranes and fortifying the electrostatic adsorption filtration capacity of the material’s trapped charges. Therefore, the incorporation of TPs not only bolstered the material’s antimicrobial efficacy but also reinforced the in-situ polarized electret effect of PVDF, consequently augmenting the high filtration efficiency and low filtration resistance capabilities of the PVDF/TPs membrane. The research found that filter membranes containing TPs exhibit exceptional filtration performance, effectively maintaining filtration resistance in 20–25 Pa while achieving a filtration efficiency of over 90% for aerosols with diameters of 2.5 μm. Notably, the PVDF/TPs membrane containing 20% TPs demonstrated outstanding filtration efficiency against 1.5 μm aerosol particles, reaching 99.98% with a filtration resistance of only 23.26 Pa, and a high inhibition rate against Staphylococcus aureus of 96.5%. The PVDF/TPs nanofiber air filtration material developed in this study presents a novel approach for high-efficiency, low-resistance, antibacterial filtration for diverse applications in antibacterial air filtration fields.