物理学报2017，Vol.66Issue(4)：233-238,6.DOI:10.7498/aps.66.046101
界面接枝羟基对碳纳米管运动和摩擦行为影响的分子动力学模拟
Influence of hydroxyls at interfaces on motion and friction of carbon nanotube by molecular dynamics simulation
摘要
Abstract
Understanding how the groups at interface influence the friction of carbon nanotubes can provide reference for their applications. In this paper, we investigate the influences of hydroxyls on motion and friction of carbon nanotube on graphite substrate by molecular dynamics simulation. The simulation cases include the ideal vertical carbon nanotube on the ideal graphite substrate, the ideal vertical carbon nanotube on the graphite with hydroxyls on the top layer, the carbon nanotube and the graphite both with hydroxyls on the surface. The results show that the lateral force of carbon nanotube changes when hydroxyls are introduced into the interfaces. If hydroxyls are only on the graphite, the fluctuation of lateral force increases obviously. The reason can be attributed to the increase of atomic surface roughness. Moreover, due to the small contact area between vertical aligned carbon nanotube and substrate, the mean friction becomes raised with hydroxyl content increasing, which is different from the conclusion obtained from silicon tip sliding on graphene with hydrogen on the surface. In that case, owing to the large contact area, the mean friction of tip reaches a maximum value at hydrogen content in a range between 5 and 10%because of the competition between the increase in the number of hydrogen atoms and the weakening of the interlock due to the increase in separation of tip from substrate. Hydrogen bond and Coulomb force appear between interfaces when hydroxyls are both on carbon nanotube and on graphite, which significantly increases friction force on carbon nanotube. And slip interfaces translate rapidly from between carbon nanotube and graphite into between graphite layers. Like the case with hydroxyls only on the graphite, the sliding of carbon nanotube perpendicular to the initial velocity also occurs when carbon nanotube and graphite are both with hydroxyls. This phenomena can be explained as the fact that the introduction of hydroxyls breaks the equilibrium of the force on the carbon nanotube in the Y direction. Moreover, the random distribution of hydroxyls causes the random motion of the carbon nanotube.关键词
碳纳米管/摩擦/羟基/氢键Key words
carbon nanotube/friction/hydroxyl/hydrogen bond引用本文复制引用
李瑞,密俊霞..界面接枝羟基对碳纳米管运动和摩擦行为影响的分子动力学模拟[J].物理学报,2017,66(4):233-238,6.基金项目
Project supported by the National Natural Science Foundation of China (Grant No. 51475039) and the National Natural Science Foundation of China (Young Scholars Program)(Grant No. 51105028). 国家自然科学基金(批准号: 51475039)和国家自然科学基金青年项目(批准号: 51105028) 资助的课题. （Grant No. 51475039）
