Facile synthesis of super-hydrophobic, electrically conductive and mechanically flexible functionalized graphene nanoribbon/polyurethane sponge for efficient oil/water separation at static and dynamic states

Abstract Graphene oxide nanoribbons (GONRs) were synthesized and functionalized by silane molecules with different hydrophobic end-groups, and silane functionalized reduced GONR (silane-f-rGONR) coated polyurethane (PU) sponge composites were fabricated via a facile dip-coating process. Fourier-transform infrared, Raman spectrum, X-ray photoelectron spectroscopy and scanning electron microscopy demonstrated that silane molecules were successfully grafted onto GONR sheets, thus producing the ability to tune surface and physical properties of PU sponge from insulating and hydrophobic to conductive and super-hydrophobic. Cyclic compression and strain-induced electrical resistance change tests indicated that the porous silane-f-rGONR coated PU (silane-f-rGONR@PU) sponge composites exhibited excellent mechanical elasticity and durability and high sensitivity of resistance change. Furthermore, the two types of silane modified sponges showed different super-hydrophobicity and tunable oleophilicity/oleophobicity. Compared to the rGONR@PU composite with poor oil/water separation at dynamic state, these porous silane-f-rGONR@PU composites not only possessed excellent oil/solvent absorption capacity and selective oil/water separation at static state, but also showed good continuous oil/solvent pumping collection with high recyclability (>97% after 10 cycles) and outstanding oil/water separation efficiency at the dynamic shaking state. This work provides a new strategy for fabricating the super-hydrophobic, electrically conductive and mechanically flexible porous rGONR based composites, showing promising application in strain sensor and oil pollution remediation fields at different environmental conditions.