Fluorine-free fabrication of durable superhydrophobic membranes for efficient oil-water separation.

The increasing occurrence of marine oil spills and industrial oily wastewater discharge demands efficient and sustainable oil-water separation technologies. Herein, we report a fluorine-free and scalable strategy to fabricate superhydrophobic nonwoven membranes via a simple two-step dip-coating process. By grafting hexadecyltrimethoxysilane (HDTMS) onto viscose/polyester substrates followed by polydimethylsiloxane (PDMS) coating, the resulting membrane exhibits excellent superhydrophobicity, mechanical robustness, and chemical stability. The optimized membrane achieves separation efficiencies up to 99.98% with high oil fluxes exceeding 5800 L·m-2·h-1, reaching 7230 L·m-2·h-1 for carbon tetrachloride. Numerical simulations of velocity, concentration, and transport pathways further elucidate the mechanism of selective permeation. In addition, the fabrication strategy demonstrates strong versatility across multiple nonwoven substrates, all showing enhanced antifouling and self-cleaning performance. This work provides a scalable and cost-effective route for constructing durable superhydrophobic materials, offering practical potential for efficient oil-water separation in complex environments.