Wavy‐Fluffy PI / MXene Nanofiber Membranes With Recyclability, Robustness, and Superhydrophobicity for Efficient, Low‐Resistance, and High‐Temperature Air Filtration

ABSTRACT Developing air purification systems with stability and reusability under harsh conditions remains a significant challenge. In this study, we designed a polyimide (PI) molecular structure and incorporated MXene nanosheets rich in active surface groups (–O, –OH, and –F) into the PI matrix using moisture‐assisted electrospinning technology. This approach successfully constructed a biomimetic, wavy, and fluffy fiber structure. The results demonstrated that the MXene‐modified PI fiber membrane exhibited outstanding superhydrophobicity (water contact angle of 151.74°), alongside superior mechanical properties (tensile strength of > 9 MPa), and thermal stability (decomposition temperature of > 500°C). The gradient pore size distribution effectively retained and captured PM while reducing air flow resistance. The fabricated filter achieved a removal efficiency of 99.99% for PM 2.5 with a low pressure drop (29.13 Pa), far lower than the 120.60 Pa pressure drop of PI OPA filters. Furthermore, the filter maintained stable filtration efficiency after five washing cycles, demonstrating excellent reusability.