Nature-Inspired Functional Materials for Advanced Oil/Water Separation

Access to clean water remains one of the most urgent global challenges, driven by rapid population growth, industrial expansion, and climate change. Efficient recycling of oil/water emulsions offers a promising solution to enhance freshwater sustainability. In this context, there is a critical need for high-performance, environmentally friendly materials that avoid toxic components. This review highlights recent advances in nature-inspired materials engineered with tailored wettability, antifouling properties, and multifunctionality. Drawing inspiration from biological systems, such as the superhydrophobic surfaces of lotus leaves, the underwater adhesion of fish scales, and the water-harvesting structures of beetle shells, we categorize these materials into three evolutionary generations: (1) conventional separation methods, (2) polymeric and Janus membranes and sponges, and (3) next-generation dynamic systems. We discuss key parameters influencing wettability, including surface chemistry, energy, roughness, and polymer molecular weight. The sustainability and industrial readiness of bioinspired separation materials are also explored. Finally, we address critical challenges, including scalability, durability under harsh conditions, and the development of cost-effective, sustainable materials for real-world deployment.