A superhydrophobic monolithic material with tunable wettability for oil and water separation

The development of a convenient method for oil-removal is of great significance for environmental protection. Here, we present a simple method for the removal of oils from water surface based on sponges that we fabricated by solution-immersion processes. The sponges exhibited high selectivity and absorption capacities for various kinds of oils when they were employed as absorptive materials. More importantly, the superhydrophobic sponge could be sustained 400 cycles of compressing test without losing their superhydrophobicity, exhibiting the high elasticity, robustness, and durability. To extend application field, superhydrophobic filter paper was used for oil-water separation. Interestingly, tunable wettability was received when oleophobic silica was employed instead of hydrophobic silica. We expected that this low-cost process can be used for oil-spill cleanup.