Falvo M R, Taylor R M, Helser A, Chi V, Brooks F P, Washburn S, Superfine R
Department of Physics and Astronomy, North Carolina Center for Nanoscale Materials, University of North Carolina, Chapel Hill 27599, USA.
Nature. 1999 Jan 21;397(6716):236-8. doi: 10.1038/16662.
Understanding the relative motion of objects in contact is essential for controlling macroscopic lubrication and adhesion, for comprehending biological macromolecular interfaces, and for developing submicrometre-scale electromechanical devices. An object undergoing lateral motion while in contact with a second object can either roll or slide. The resulting energy loss and mechanical wear depend largely on which mode of motion occurs. At the macroscopic scale, rolling is preferred over sliding, and it is expected to have an equally important role in the microscopic domain. Although progress has been made in our understanding of the dynamics of sliding at the atomic level, we have no comparable insight into rolling owing to a lack of experimental data on microscopic length scales. Here we produce controlled rolling of carbon nanotubes on graphite surfaces using an atomic force microscope. We measure the accompanying energy loss and compare this with sliding. Moreover, by reproducibly rolling a nanotube to expose different faces to the substrate and to an external probe, we are able to study the object over its complete surface.
了解相互接触物体的相对运动对于控制宏观润滑和粘附、理解生物大分子界面以及开发亚微米级机电设备至关重要。一个物体在与另一个物体接触时进行横向运动，既可以滚动也可以滑动。由此产生的能量损失和机械磨损在很大程度上取决于发生哪种运动模式。在宏观尺度上，滚动比滑动更可取，并且预计在微观领域也将发挥同样重要的作用。尽管我们在理解原子尺度上的滑动动力学方面取得了进展，但由于缺乏微观长度尺度的实验数据，我们对滚动没有类似的深入了解。在这里，我们使用原子力显微镜在石墨表面实现了碳纳米管的可控滚动。我们测量了伴随的能量损失，并将其与滑动进行比较。此外，通过可重复地滚动纳米管，使不同的面暴露于基底和外部探针，我们能够研究该物体的整个表面。
