Superhydrophobic surfaces for oil-water separation

Oil spill in the environment is one of the serious issues faced around the world. Efficient oil removal and collection from water is a challenging task. Numerous costly and time-consuming physical, chemical, and biological methods had been adopted for oil spill clean-up. Sponges or membranes having both superhydrophobic and superoleophilic properties can be utilized for easy oil–water separation. On such surfaces, the water droplet attains contact angle greater than 150 degrees (superhydrophobic) and oil droplets quickly get absorbed with contact angle nearly equal to 0 degrees (superoleophilic). The polymer-modified sponges/membranes can selectively absorb the oil and effectively repel the water with high selectivity and recyclability. In addition, the polymeric sponges/membranes can show excellent hydrophobicity, robustness, and flexibility due to the chemical and physical properties of the polymers. Numerous polymer-modified sponges/membranes exhibiting excellent oil absorption capacity, selectivity, recyclability, and mechanical durability are discussed in this chapter. The innovative ideas and methods utilized for the preparation of superhydrophobic sponges/membranes are also reviewed. These smart surfaces can be produced for industrial scale and used for efficient and controlled oil-water separation in high-risk areas.