Superhydrophobic polyvinylidene fluoride nanofibrous membranes with stable hierarchical structures for protective textiles

Waterproof and breathable (W&B) membranes, resisting the intrusion of liquid water while allowing transmission of vapor, have been widely applied in various applications. However, there are still great challenges to construct superhydrophobic and mechanically robust W&B membranes. Here, we present a facile strategy to prepare superhydrophobic nanofibrous membranes by combining humidity-induced electrospinning with thermal-pressing treatment. The hierarchical rough structures generated by humidity-induced phase separation of polyvinylidene fluoride jets endow the fiber with superhydrophobicity. Meanwhile, the thermal-pressing manipulation ensures that strong physical bonding exists between nanofibers, which greatly improves the membrane's mechanical and waterproof performances. Significantly, the resulted membranes exhibited desirable superhydrophobicity with water contact angle of 151°, remarkable water and oil intrusion pressures of 81.8 and 36.2 kPa, respectively, high water vapor transmission rate of 7948 g m−2 d−1, and satisfactory tensile strength of 8.1 MPa. The successful development of such membranes provides a new inspiration for the manufacture of superhydrophobic protective membranes.