Department of Chemical Physics, School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv, Israel.
Chemphyschem. 2013 Aug 5;14(11):2376-91. doi: 10.1002/cphc.201300259. Epub 2013 Jun 18.
Nanoscale tribology is an active and rapidly developing area of research that poses fundamental scientific questions that, if answered, may offer great technological potential in the fields of friction, wear, and lubrication. When considering nanoscale material's junctions, surface commensurability often plays a crucial rule in dictating the tribological properties of the interface. This Review surveys recent theoretical work in this area, with the aim of providing a quantitative measure of the crystal lattice commensurability at interfaces between rigid materials and relating it to the tribological properties of the junction. By considering a variety of hexagonal layered materials, including graphene, hexagonal boron nitride, and molybdenum disulfide, we show how a simple geometrical parameter, termed the "registry index" (RI), can capture the interlayer sliding energy landscape as calculated using advanced electronic structure methods. The predictive power of this method is further demonstrated by showing how the RI is able to fully reproduce the experimentally measured frictional behavior of a graphene nanoflake sliding over a graphite surface. It is shown that generalizations towards heterogeneous junctions and non-planar structures (e.g., nanotubes) provide a route for designing nanoscale systems with unique tribological properties, such as robust superlubricity. Future extension of this method towards nonparallel interfaces, bulk-material junctions, molecular surface diffusion barriers, and dynamic simulations are discussed.
纳米摩擦学是一个活跃且快速发展的研究领域，提出了一些基本的科学问题，如果得到解答，可能会在摩擦、磨损和润滑领域带来巨大的技术潜力。在考虑纳米材料的连接处时，表面协调性通常起着至关重要的作用，决定着界面的摩擦学特性。这篇综述调查了该领域的最新理论工作，旨在提供一种定量的方法来衡量刚性材料之间界面的晶格协调性，并将其与连接的摩擦学特性联系起来。通过考虑各种六方层状材料，包括石墨烯、六方氮化硼和二硫化钼，我们展示了如何使用一个简单的几何参数，称为“配位数指数”（RI），来捕捉使用先进的电子结构方法计算的层间滑动能量景观。通过展示 RI 如何完全再现实验测量的石墨烯纳米片在石墨表面滑动的摩擦行为，进一步证明了该方法的预测能力。结果表明，对异质连接和非平面结构（如纳米管）的推广为设计具有独特摩擦学特性的纳米级系统提供了一种途径，例如鲁棒的超滑。讨论了该方法向非平行界面、体材料连接、分子表面扩散势垒和动力学模拟的扩展。
