Amphiphobic fluorinated polyurethane composite microfibrous membranes with robust waterproof and breathable performances

Amphiphobic, microporous polyurethane (PU) composite microfibrous membranes exhibiting robust waterproof and breathable performances were prepared by the introduction of a novel synthesized fluorinated PU (FPU) containing head perfluoroalkane segment. By employing the FPU incorporation, the pristine PU membranes were endowed with the superhydrophobicity with water contact angle of 156 degrees and the oleophobicity with oil contact angle of 145 degrees. The role of FPU for the tuning of the morphology, surface wettability and mechanical property of resultant membranes were discussed, and a plausible two-step break mechanism upon the external stress is proposed. The quantitative fractal dimension analysis using N-2 adsorption method has confirmed the correlation between the hierarchical roughness and amphiphobicity. Furthermore, the as-prepared membranes exhibited high water resistance (39.3 kPa), good air permeability (8.46 L m(-2) s(-1)) and water vapor transmittance (0.384 kg m(-2) h(-1)), and comparable tensile strength (10 MPa), suggesting their use as promising materials for a variety of potential applications in protective clothing, bioseparation, membrane distillation, tissue engineering and catalyst carriers, etc., and also provided new insight into the design and development of functional microfibrous membranes through FPU incorporation.