Xiong Wei, Liu Jefferson Zhe, Ma Ming, Xu Zhiping, Sheridan John, Zheng Quanshui
Department of Engineering Mechanics, Tsinghua University, Beijing, China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2011 Nov;84(5 Pt 2):056329. doi: 10.1103/PhysRevE.84.056329. Epub 2011 Nov 28.
Using equilibrium and nonequilibrium molecular dynamic simulations, we found that engineering the strain on the graphene planes forming a channel can drastically change the interfacial friction of water transport through it. There is a sixfold change of interfacial friction stress when the strain changes from -10% to 10%. Stretching the graphene walls increases the interfacial shear stress, while compressing the graphene walls reduces it. Detailed analysis of the molecular structure reveals the essential roles of the interfacial potential energy barrier and the structural commensurateness between the solid walls and the first water layer. Our results suggest that the strain engineering is an effective way of controlling the water transport inside nanochannels. The resulting quantitative relations between shear stress and slip velocity and the understanding of the molecular mechanisms will be invaluable in designing graphene nanochannel devices.
通过平衡和非平衡分子动力学模拟，我们发现对形成通道的石墨烯平面施加应变能够显著改变水通过该通道时的界面摩擦力。当应变从 -10% 变化到 10% 时，界面摩擦应力有六倍的变化。拉伸石墨烯壁会增加界面剪切应力，而压缩石墨烯壁则会降低界面剪切应力。对分子结构的详细分析揭示了界面势能垒以及固体壁与第一层水之间结构适配性的重要作用。我们的结果表明，应变工程是控制纳米通道内水传输的有效方法。由此得到的剪切应力与滑移速度之间的定量关系以及对分子机制的理解，对于设计石墨烯纳米通道器件将具有重要价值。
