Highly breathable and durable waterproof polyimide electrospun nanofibrous membrane for potential reusable protective clothing application: Preparation, characterization and performance

The quest for a highly breathable protective clothing with good barrier performance is rapidly rising, especially in the fight against the COVID-19 pandemic. However, commercial protective clothing usually experiences tradeoff between air permeability and barrier performance. Herein, a highly breathable and durable polyimide (PI)based protective clothing material with good barrier performance was fabricated by electrospinning. The structure of PI electrospun nanofibrous membranes (PI-ENMs) was optimized in terms of mechanical strength, filtration efficiency and air permeability. The results showed that the PI-ENM with 500 nm diameter prepared by electrospinning for 4 h had high filtration efficiency (96.13 %), low pressure drop (57.1 Pa) and high-quality factor (0.057 Pa-1). The optimized PI-ENM had a high bacterial filtration efficiency of 99.48 %, which meant that it would possess good microbial barrier performance in practical applications. Due to the low air resistance, the PI-ENM demonstrated a high air permeability of 265.44 mm s- 1, which was 40-160 times that of commercial protective clothing. An ultra-thin layer of polydimethylsiloxane (PDMS) was coated on the thermal stable PIENMs via chemical vapor deposition to obtain PI-ENM@PDMSs, of which the fire resistance was further enhanced without compromising filtration efficiency and resistance. Moreover, the PI-ENM@PDMSs exhibited strong hydrophobicity, robust mechanical strength, and excellent stability, and can be easily reused via common sterilization methods without impacting its protection performance. Therefore, PI-ENM@PDMSs is a promising candidate for reusable breathable protective clothing.