title: Supramolecular surface modification and dispersion of graphene in water and organic solvents.
abstract: Graphene sheets have been dispersed in water and organic solvents by noncovalent surface modification with the assistance of bifunctional molecule pyrene-adamantane (Py-Ad) carrying a pyrene moiety. Lipophilic graphene sheets have been obtained in the form of graphene-Py-Ad in a wide variety of organic solvents, such as dimethyl sulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylformamide, and tetrahydrofuran, in which the adamantane moieties served as the three-dimensional steric groups keeping the graphene sheets from stacking. Supramolecular complexes were employed as the dispersing agent for graphene formed through in situ reduction by hydrazine or hydroquinone. Water-dispersible graphene sheets have been obtained in the form of graphene-Py-Ad-bMCD (methylated beta-cyclodextrin, bMCD), in which the pyrene moiety attached to graphene by pi-pi stacking interaction and hydrophobic effect, and the adamantane group formed complex with bMCD, yielding a supramolecular system that made graphene sheets dissolved in water through the formed hydrophilic cyclodextrin shell. The resulting supramolecular complexes were characterized by atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, thermal gravimetric analysis, transmission electron microscopy, ultraviolet-visible spectroscopy, fluorescence spectroscopy, and Raman spectroscopy.
authors: National Center for Nanoscience and Technology, Beijing 100190, China.
authors: Sheng-Zhen
authors: SZ
authors: Zu
authors: Ding
authors: D
authors: Zhou
authors: Bao-Hang
authors: BH
authors: Han