Biomimetic Multi-Responsive Superwettable Materials for Oil–Water Separation

Industrial oily wastewater discharges and marine oil spills pose a serious threat to ecosystems. A new strategy for efficient and controllable oil-water separation is provided by smart-responsive wettability materials, owing to their ability to dynamically switch surface wettability in response to external stimuli. Under this premise, we reviewed the research progress and applications of such materials. First, we described the theoretical basis of wettability and the mechanism of oil-water separation. Subsequently, we comparatively analyzed the structural characteristics and separation properties of four types of special wettable materials. We focused on eight categories of smart response wetting materials: temperature, pH, light, electricity, gas, ion, solvent, and multi-response. For each type, we analyzed the response mechanisms, advantages, and limitations in oil-water separation. In addition, we compared the advantages and disadvantages of key preparation techniques such as layer-by-layer self-assembly, electrostatic spinning, and surface-initiated atom transfer radical polymerization. Finally, we summarized the current research status and challenges in the field of smart-responsive wetting materials and looked forward to future development directions.