Superhydrophobic modification of polyurethane sponge for the oil-water separation

In this work, the fluoroalkylsilane-modified SiO2 nanoparticles (NPs) were immobilized on the polyurethane sponges by a highly efficient drop-coating method using different polymers including poly(vinylidene fluoride), poly(vinylidene fluoride-ter-trifluoroethylene-ter-chlorotrifluoroethylene), polystyrene, and polyurethane as the adhesives to achieve the superhydrophobic modification of the polyurethane sponges for oil-water separation. The successful fluoroalkylsilane modification for the SiO2 NPs was confirmed by TEM, SEM, FITR, XPS, and TGA. Furthermore, the surface-modified polyurethane sponges were investigated by SEM and two-dimensional EDS mapping. The contact angles of the surface-modified polyurethane sponges were in the range of 151.6°–154.3°, which confirmed the realization of the superhydrophobic modification for the polyurethane sponges. The demonstration experiments showed that the resulting surface-modified polyurethane sponge could effectively remove oil from the oil-water mixture by direct absorption or gravity-driven filtration. Moreover, the surface-modified polyurethane sponges possessed not only high absorption capability for different oils including peanut oil, pump oil, and silicone oil but also good reusability. We believe that such novel surface-modified polyurethane sponges might be potential candidates for the oil-water separation.