Research of Nanotribology with Central Focuses on Carbon Nanotubes

本研究旨在研究先进碳材料的纳米摩擦学特性，并以碳纳米管为重点，进一步指导这些材料在纳米和微机械、下一代磁记录系统和生物纳米器件中的应用。本文主要从空气和真空中原子力显微镜得到的结果进行了分析讨论。碳纳米管具有新的、独特的摩擦学性能：在μ牛顿作用力下，碳纳米管无粘附，而10^0的超高摩擦系数与刀尖半径、反表面硬度、滑动速度和环境湿度的关系不大，无犁削和无磨损。在m牛顿作用力下，碳纳米管的摩擦系数降低了10^<-1>，这是由于碳纳米管在滑动界面处变形转化为石墨片，在牛顿作用力下，碳纳米管的摩擦系数降低了10^<-2>，主要是由于使用了润滑油。碳纳米管在摩擦过程中产生自组装结构，是一种很有前途的润滑油纳米润滑剂。在超高真空中，通过选择与单碳纳米管接触的材料，可以区分范德华力和π-π*相互作用。洋葱状碳在特高压下表现出0.005的低摩擦系数，并且在真空和油中也有希望成为低摩擦材料。分子束外延法制备的富勒烯C_<60>表现出随作用力变化的摩擦特性。在nNewton的作用力下，产生中等摩擦力，而在mNewton以上的作用力下，产生高摩擦力，导致运动中断。因此，通过有效利用这些先进碳材料的纳米摩擦学特性，可以设计纳米和微机械的悬吊/停止。

The aim of this study was to investigate nanotribological properties of advanced carbon materials with focuses on carbon nanotube and further to guide the way of applying these materials to nano and micro machines, magnetic recording systems for the next generation and bio-nano devices. Analytical discussion was made from the results mainly obtained by atomic force microscopy both in air and in vacuum. New and unique tribological properties of carbon nanotubes can be written as: At μ Newton applied forces, carbon nanotubes provided null adhesion, whereassuperhigh friction coefficient of 10^0, exhibited little dependence on tip radius and hardness of the counter face, on sliding speed, and on humidity of environment, and showed no plowing and no wear. At mNewton applied forces, carbon nanotubes showed lowered friction coefficient of 10^<-1>, because of their deformed transformation into graphite sheet at the sliding interface, and at Newton applied forces, carbon nanotubes showed low friction coefficient of 10^<-2>, and predominant low friction coefficient resulted with a use of lubrication oil. Carbon nanotubes created self-assembled structure under friction processes, and are promising as nanolubricant in lubricating oil. At nNewton applied forces in ultrahigh vacuum, it is possible to distinguish van der Waals forces from π-π* interaction by selecting a material contacting with the single carbon nanotube. Onion like carbon showed low friction coefficient of 0.005 in UHV, and is also promising as low friction material usable both in vacuum and in oil. Fullerene C_<60> prepared by molecular beam epitaxy showed friction characteristics depending on applied forces. At nNewton applied forces, medium friction resulted, while over mNewton applied forces, high friction that caused interruption of motion occurred. Therefore, sling/stopping of nano and micro machines can be designed by effectively making use of nanotribological properties of these advanced carbon materials.