Superhydrophobic, compressible, and reusable polyvinyl alcohol-wrapped silver nanowire composite sponge for continuous oil-water separation

摘要

Herein, we applied a coaxial cable type polyvinyl alcohol-wrapped silver nanowire (Ag-PVAs) composite sponge as adsorbent material for oil/water separation. The Ag-PVAs sponge was prepared by two steps of hydrothermal and freeze-drying, and then modified with polydimethylsiloxane (PDMS) to reduce its surface energy. The modified Ag-PVAs sponge (f-PDMS) displayed superhydrophobic property due to its porous structure and low surface energy. Importantly, the f-PDMS has 14 times of maximum stress, compared with that of Ag-PVAs. Meanwhile, the maximum compressive stress of the f-PDMS sponge can still be maintained at 87.3% after 50 stress-strain cycles at 70% strain. Moreover, the f-PDMS sponge exhibits good adsorption properties for various oils with different densities and can be reused by extrusion and evaporation. Continuous oil/water separation can also be achieved with the aid of a vacuum pump, which will make it a powerful competitor for large-scale industrial separation of oil/organic solvents and water mixtures.