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 degrees-454.3 degrees, 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.