Fabrication of sustainable and durable superwetting cotton fabrics with plant polyphenol for on-demand oil/water separation

Superwetting cotton fabrics with surface wettability from underwater superoleophobic to superhydrophobic were designed and prepared by modification with polymerized plant polyphenol for on-demand oil/water separation. Hydrophilic poly(tannic acid) (PTA) particles were in-situ deposited onto the surface of polyethyleneimine (PEI)-coated cotton fabric. The resulting underwater superoleophobic cotton fabric (UWSOCF) was a water-removing material to separate water/light oil mixtures with a separation efficiency higher than 99.8%. After modifying UWSOCF with hydrophobic octadecylamine (ODA), superhydrophobic cotton fabric (SHCF) was obtained. SHCF was an oil-removing material suitable for separating water/heavy oil mixtures with a separation efficiency higher than 96%. Both UWSOCF and SHCF exhibited excellent mechanical robustness and environmental durability and could resist mechanical abrasion, tape peeling, high temperatures, organic solvents, and acidic/alkali erosion.