Journal Article


Jonathan N Coleman
Sukanta De
Umar Khan
Paul J King
Mustafa Lotya



materials testing macromolecular substances ultrastructure nanotechnology surface properties colloids graphite crystallization molecular conformation chemistry nanostructures surface active agents particle size

High-concentration, surfactant-stabilized graphene dispersions. (2010)

Abstract A method is presented to produce graphene dispersions, stabilized in water by the surfactant sodium cholate, at concentrations up to 0.3 mg/mL. The process uses low power sonication for long times (up to 400 h) followed by centrifugation to yield stable dispersions. The dispersed concentration increases with sonication time while the best quality dispersions are obtained for centrifugation rates between 500 and 2000 rpm. Detailed TEM analysis shows the flakes to consist of 1-10 stacked monolayers with up to 20% of flakes containing just one layer. The average flake consists of approximately 4 stacked monolayers and has length and width of approximately 1 mum and approximately 400 nm, respectively. These dimensions are surprisingly stable under prolonged sonication. However, the mean flake length falls from approximately 1 mum to approximately 500 nm as the centrifugation rate is increased from 500 to 5000 rpm. Raman spectroscopy shows the flake bodies to be relatively defect-free for centrifugation rates below 2000 rpm. The dispersions can be easily cast into high-quality, free-standing films. The method extends the scope for scalable liquid-phase processing of graphene for a wide range of applications.
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Full list of authors on original publication

Jonathan N Coleman, Sukanta De, Umar Khan, Paul J King, Mustafa Lotya

Experts in our system

Jonathan Coleman
Trinity College Dublin
Total Publications: 217
Umar Khan
Trinity College Dublin
Total Publications: 37
Paul J King
Trinity College Dublin
Total Publications: 15
Mustafa Lotya
Trinity College Dublin
Total Publications: 19