Electret nanofibrous membrane with enhanced filtration performance and wearing comfortability for face mask

Airborne particulate matter (PM) pollution has become a serious threat to human health, thus it is highly desired for a high-filtration-performance and good-wearing-comfort face mask. Herein, a highly breathable and thermal comfort filter medium consisting of electret polyethersulfone/barium titanate nanofibrous membrane (PES/BaTiO₃ NFM) integrated on a nonwoven polypropylene substrate was developed. Benefiting from the high porosity and optimized injection charge energy, the PES/BaTiO₃ membrane was endowed with a good air permeability of 743 mm s^-1, a modest water vapor permeability of 6.24 kg m^-2 d^-1, and an enhanced charge storage stability. In addition, the electret PES/BaTiO₃ NFM1.5 medium with a low basis weight of 4.32 g m^-2 still shows a high filtration efficiency of 99.99% and a low pressure drop of 67 Pa after being treated at 200 °C for 45 min, which is better than that of commercial media. Moreover, 3D simulation based on the characters of composite membrane was processed to graphically express the airflow distribution during the filtration process. Significantly, the NFM1.5 with a high infrared (IR) transmittance of 93.4% led to an effective radiative cooling to human body radiation. This multifunctional fibrous medium design may provide new insights into the development of environmental adaptive protection materials.