A porous Janus nanofiber membrane with unidirectional water vapor transport for efficient dust personal protection

The generation of coal dust affects all aspects of coal mining, posing a serious threat to miner's health. However, developing a novel respirator material with high respiratory efficiency and low resistance poses a significant challenge. Additionally, traditional masks can cause water vapor from exhaled breath to condense into minuscule droplets that adhere to the inside of the mask, reducing comfort. In this study, a porous Janus nanofiber membrane was successfully prepared using sequential electrospinning technology combined with post-treatment techniques. Due to its unique porous structure and double-sided anisotropy, the Janus nanofiber membrane achieves high filtration efficiency and low air resistance simultaneously. Under a high-intensity respiration rate of 85 L/min, the Janus nanofiber membrane maintains a filtration efficiency of 99.98 % and a pressure drop of 134.7 Pa. Moreover, the Janus nanofiber membrane can effectively transport water vapor from exhaled breath to the external environment. The external hydrophobic membrane effectively intercepts water mist from the air. The Janus nanofiber membrane water vapor transmittance can reach 2633.863 cm3/m2·d·Pa. The contact angle of the hydrophobic side of the nanofiber membrane reached 145°, while the contact angle of the hydrophilic side reached 0° after 3 s of water droplet exposure. These features greatly improve user comfort. Taken together, our findings demonstrate the promising potential of the newly developed Janus nanofiber membrane for individual protection.