Size Fractionation of Graphene Oxide Sheets by pH-Assisted Selective Sedimentation

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 μm2 at...

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Bibliographic Details
Published in:Journal of the American Chemical Society 2011-04, Vol.133 (16), p.6338-6342
Main Authors: Wang, Xiluan, Bai, Hua, Shi, Gaoquan
Format: Article
Language:English
Subjects:
Graphite - chemistry
Hydrogen-Ion Concentration
Microscopy, Electron, Scanning
Oxides - chemistry
Particle Size
X-Ray Diffraction
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Summary: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 μm2 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.
ISSN:0002-7863
1520-5126
DOI:10.1021/ja200218y