Toward the design of highly waterproof‐breathable electrospun nanofiber membrane based on π–π interactions

Abstract Waterproof and breathable nanofiber membranes are highly desirable for protective textiles; however, the practical application of nanofiber membranes is limited by fluorine‐containing material addition or complicated post‐treatment. Herein, we reported unique fluorine‐free polyurethane (PU)/poly(styrene‐ b ‐s‐ b ‐styrene) (SBS) nanofiber membranes by a facile direct electrospinning. Owing to the addition of SBS, the hydrophobicity, waterproofness, and mechanical properties of PU nanofiber membranes were dramatically enhanced. Furthermore, the highly interconnective channels were constructed after the introduction of SBS into the PU nanofiber membrane, which resulted in enhanced breathability. The enhancement in the comprehensive performance of the PU/SBS composite nanofiber membrane might be attributed to the π–π interactions between SBS and PU. By adjusting the concentration of the PU/SBS, fluorine‐free PU/SBS nanofiber membranes were optimized systematically, exhibiting satisfactory waterproofness (hydrostatic pressure, 47.4 kPa), acceptable breathability (water vapor transition rate, 5.6 kg m −2 d −1 ), and outstanding mechanical properties (breaking strength, 5.7 MPa; breaking elongation, 387.9%). The PU/SBS‐14 nanofiber membrane is ideal for wearable textiles, especially for outdoor protective clothing, wound dressings, and medical gowns.