Robust and Durable Superhydrophobic Polyurethane Sponge for Oil/Water Separation

With the purpose of purging and recycling oil and organic solvent from a water surface, a superhydrophobic polyurethane (PU) sponge was fabricated through a combined method of interfacial polymerization (IP) and molecular self-assembly. The as-prepared sponge has a superwetting characteristic of superlipophilicity in atmosphere and superhydrophobicity both in atmosphere and under oil, and it can quickly and selectively absorb various kinds of oils up to 29.9 times its own weight. More importantly, because of a covalent combination of the sponge skeleton and the polyamide thin film from IP, the superhydrophobic sponges could be reused for oil/water separation over 500 cycles without losing its superhydrophobicity, showing the highest reusability among the reported absorptive materials. The superhydrophobic sponge also can be used in the continuous absorption and expulsion of oils and organic solvents from water surfaces with the help of a vacuum pump. All of these features make the sponge a promising candidate material for oil-spill cleanups.