科研之友
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摘要
We prepared few-layer graphene samples by liquid-phase exfoliation in ethanol. By controlling the solvent temperature, sonication time and power, and centrifugation speed and time, we fabricated several-layer graphene from highly oriented pyrolytic graphite (HOPG). The obtained supernatant was added dropwise onto freshly cleaved mica surfaces. Nanotribological study of the samples under high vacuum by atomic force microscope (AFM) showed that frictional force decreased as the number of monolayers (ML) of graphene increased, and their frictional coefficient remained constant when the sample was thicker than about 4 ML. When the coverage reached 7 ML, the frictional coefficient was close to zero. In wear experiments, 2-ML graphene exhibited better wear resistance than the 4-ML sample and had no dependence on directional friction. We also measured the adhesion force of samples containing different numbers of layers of graphene and the mica surface, and found that substrate adhesion is not the main reason for the wear resistance properties of 2-ML graphene. Compared with single-layer graphene, the low friction coefficient of few-layer graphene makes it promising for application in areas such as data storage devices, nanoelectromechanical systems, and anti-wear coatings.
- 出版日期2013-7
- 单位上海交通大学
