Hydrogel as a Superwetting Surface Design Material for Oil/Water Separation: A Review

Abstract Oil/water separation is significantly important to the ecological system. A variety of materials have been explored to address this issue via the rational control of surface morphology, nanostructures, and chemical compositions of materials. Among them, hydrogels emerge as a potential option because of their interfacial features (i.e., superhydrophilicity and underwater superoleophobicity). Hydrogel‐coated materials are well studied and proven to have high efficiency in separating different oil/water mixtures under various conditions. This review provides an extensive summary and analyses on the progress of this topic, mainly focusing on the preparation of corresponding hydrogel‐coated materials and their performance and mechanism in oil/water separation. The perspective and the outlook for future studies are also given. This article may provide readers with guidance to quickly enter this area and give researchers some inspiration for future work.