title: Size fractionation of graphene oxide sheets by pH-assisted selective sedimentation.
abstract: Graphene oxide (GO) sheets prepared by Hummers' method have been separated into two portions with large (f1) or small (f2) lateral dimensions from their aqueous dispersion. This method is based on the selective precipitation of GO sheets with lateral dimensions mostly (>90%) larger than 40 μm(2) at a pH value of 4.0 because of their larger hydrophobic planes and fewer hydrophilic oxygenated groups. The hydrazine reduced Langmuir-Blodgett (LB) films of f1 showed much higher conductivities than those of f2. Furthermore, the thin film of f1 prepared by filtration exhibited a smaller d-space and much higher tensile strength and modulus than those of f2 films. The one-step size fractionation method reported here is simple, cheap, efficient, and environmentally friendly, which can be used for the size fractionation of GO sheets in large scale.
authors: Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing 100084, People's Republic of China.
authors: Xiluan
authors: X
authors: Wang
authors: Hua
authors: H
authors: Bai
authors: Gaoquan
authors: G
authors: Shi
mesh_terms: D006108:Graphite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D010087:Oxides / Q000737:chemistry*; D010316:Particle Size; D014961:X-Ray Diffraction
chemical_list: D010087:Oxides; D006108:Graphite