β-cyclodextrin dimer cross-linked self-healing hydrogels and their application in oil–water separation

Functional self-healing materials have garnered significant attention due to their customizable properties and ability to repair microstructural defects, restore functionality in response to external stimuli or through autonomous mechanisms. In this study, the hydroxyl groups on β-cyclodextrin dimer were functionalized with 3-acrylamidophenylboronic acid monohydrate and were subsequently used as a cross-linker in the copolymerization with acrylamide to form self-healing hydrogels, which exhibited enhanced water absorption abilities. When microporous stainless-steel meshes were coated with these self-healing hydrogels, the meshes can effectively separate oil–water mixtures using gravity filtration, achieving separation efficiencies of over 99.5%. This outstanding performance is attributed to the hydrogels’ exceptional superhydrophilicity and underwater superoleophobicity. Furthermore, repeated separation tests with various oil types confirmed the durability and effectiveness of the hydrogel-coated mesh for practical applications in oil–water separation. Our work highlights the significant potential of self-healing hydrogel-coated meshes as a robust, efficient, and reusable platform for sustainable oil–water separation in environmental and industrial applications.