Hierarchically porous superhydrophobic sponge for oil-water separation

Superhydrophobic vinyl terminated polydimethylsiloxane embedded polystyrene sponge (V-PDMS/PS) with hierarchical structure for efficient oil-water separation was constructed by the dual-emulsion-template route, based on polymerization of the water-in-oil (W/O) type high internal phase emulsions (HIPEs). A series of vinyl terminated polydimethylsiloxane (V-PDMS) was adopted as the organic phase as well as the hydrophobic modification reagent. Finally, the sponge material was composed of polystyrene (PS) skeleton embedded with V-PDMS chain, which exhibited an enhanced thermal stability compared with the pure polystyrene sponge. The obtained sponge exhibited an outstanding oil collection performance of 55.6 g/g–119.5 g/g towards representative oil pollutant. The polystyrene sponge features excellent recyclability, with about 90% recovery rate just by simple compression. Besides, it showed superhydrophobicity with water contact angles (WCAs) exceeding 150°, deriving from the hierarchically porous structure and the low-surface-energy of the V-PDMS. It also exhibited superoleophilicity with oil contact angle approaching 0°.