Flexible and Mechanically Robust Nanofiber Membrane with Candle Soot-Induced Rough Surface for Organic Liquid Separation

Robust superwetting separation membranes with high performance are highly suitable for separating organic liquids (OLs). Current OLs separation membranes do not conform to practical applications due to complex operations, high costs, and low mechanical stabilities. Herein, a simple one-step coaxial electrostatic spinning strategy was used to prepare candle soot (CS) reinforced flexible under-liquid superlyophobic fiber membrane (FUSFM), where the wetting behavior was regulated by forming stable liquid-injection interfaces. The permeation flux and separation efficiency of FUSFM-0.15 for OLs were 12,000 L m–2 h–1 and 99.7%, respectively. Compared with the modification by direct doping, the coaxial electrospinning ensured that CS nanoparticles were only distributed on the fiber surface to form a hierarchical roughness structure. The formation of defects due to the agglomeration of CS nanoparticles was prohibited in the fiber, so the FUSFM exhibited excellent mechanical properties (15 MPa). Moreover, the enhancement mechanism of nanoparticles on the mechanical properties of the membrane was analyzed by finite element simulation, and this synthesis strategy was also applied to other 0-dimensional nanoparticles. The FUSFM-0.15 demonstrates excellent flexibility, high chemical stability, and outstanding mechanical robustness. This work may inspire the design and preparation of a robust and cost-effective separation membrane for OLs.