A novel chemical crosslinking enabled special wettability coating for higher efficiency oil–water separation

The environmental destruction caused by oil pollution has been an inescapable fact, and there is an urgent need for efficient separation materials to solve this problem. Generally speaking, Polyethylene terephthalate (PET) is relatively easy to modify into super-hydrophobic/super-oleophilic membranes due to its hydrophobic ester groups. However, there are some challenges in preparing them as underwater super-oleophobic films. Herein, this paper proposes a two-step coating method for the preparation of underwater super-oleophobic PET films by coating the surface of PET films with silicone to form a cross-linked layer through polymerization (Cross-linking), followed by coating the surface of the cross-linked layer with a fluorinated compound/SiO₂ (Coating-F@SiO₂). Experiments have shown that the new filter membrane exhibits excellent corrosion resistance and special wettability (> 150°). After 30 filtration cycles, it still maintains excellent oil–water separation efficiency (> 99.9%). This simple method for preparing oil–water separation membrane enriches the treatment process of oil pollution. The large-area and low-cost preparation route also provides a prospect for scalable applications.