Self-assembly of graphene oxide on the surface of aluminum foil

We have demonstrated a special phenomenon, that the self-assembly of graphene oxide (GO) occurred on the matte surface of Al foil. Paper-like GO and GO composite films, including GO-polysaccharide and GO-poly(vinyl alcohol), were formed through water/air and water/Al interfacial interactions and the hydrophobicity of GO which is partially reduced in the presence of the Al foil. GO was first confirmed to be partially reduced on the surface of Al foil by wide angle X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. Additionally, a three-dimensional (3D) macrostructural GO hydrogel composed of GO sheets in a random order was observed at the interface between the GO aqueous solution and Al foil. The mechanism through which the hydrogel formed was attributed to the initial absorption of the GO sheets on the surface of the Al foil through the liquid/solid interfacial and hydrogen-bonding interactions at the liquid/solid interface, and then the selfassembly though pi-pi stacking, Al3+ cross-linking, and the hydrophobicity of the partially reduced GO. We have described a very simple and mild method to prepare GO-based thin films and 3D-macroscopic hydrogels with partially reduced GO.