New recipe makes cheap, easy nanomaterials
With soap, water, graphite and the whirl of a blender’s blades, researchers can serve up big batches of graphene, a material that shows promise for use in myriad high-tech applications.
Graphene sheets are single-atom-thick layers of carbon that, when stacked, make up graphite. Individual sheets are sturdy, transparent and excellent conductors of electricity, giving them enormous potential for use in plastics, superconductors and many other materials. But making large amounts is tricky.
Recipes that rely on chemicals to peel wafer-thin layers off graphite run the risk of creating chinks in graphene’s chicken wire arrangement of atoms. Ultrasonic waves can shimmy the layers apart but work only for small batches.
Researchers led by Jonathan Coleman of Trinity College Dublin found that simple blenders can form graphene sheets from hundreds of liters or more of graphite slurry without disturbing the atomic latticework.
As some of the slurry is sucked into the blender’s blades, it rushes past slower-moving slurry, creating a shearing force that strips off 100- to 2,000-nanometer-long graphene sheets from graphite flakes. The researchers used the graphene to reinforce plastics and act as conductive elements, demonstrating that they could work in batteries and solar cells. The team reports the findings April 20 in Nature Materials.
K.R. Paton et al. Scalable production of large quantities of defect-free few-layer graphene by shear exfoliation in liquids. Nature Materials. Published online April 20, 2014. doi: 10.1038/nmat3944.
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