缺陷对碳纳米管摩擦与运动行为的影响

本文采用分子动力学方法研究了公度、无公度情况下含空位、Stone-Thrower-Wales(STW)型缺陷的单壁碳纳米管(SWCNT)在石墨基底上的摩擦与运动行为.结果表明,公度时缺陷的存在导致了界面局部无公度,减小了摩擦.随着碳纳米管底部STW缺陷的增多,碳纳米管变形增大,侧向力波动的幅值减小,局部无公度性增强,摩擦减小.含空位缺陷的碳纳米管所受的摩擦力明显大于含STW缺陷的碳纳米管,原因在于含空位缺陷的碳纳米管在运动的后期出现了明显的翻转现象,增大了能量耗散.无公度时,碳纳米管与石墨基底间的摩擦力很小,缺陷对其摩擦力影响不大,原因在于无论是否含有缺陷,碳纳米管与石墨组成的界面的无公度性差别不大.

Influence of defects on friction and motion of carbon nanotube

Motion and friction of carbon nanotubes with vacancy defects or Stone-Thower-Wales (STW) defects on them are investigated in commensurate states and incommensurate states by molecular dynamics simulation. Results show that defects lead to incommensurate state in part of interfaces, thus decreasing the friction. More amount of STW defects would cause larger distortion of carbon nanotube, smaller lateral force amplitude, more local incommensurate state of interfaces and smaller friction. The friction of carbon nanotube with vacancy defects is obviously larger than carbon nanotube with STW defects. The reason is that the carbon nanotube with vacancy defects will change its motion in later period of motion, which can increase energy dissipation. Defects barely have influence on the friction of carbon nanotubes in incommensurate state because interfaces are all in incommensurate state whether they are having defects or not.
Keywords： carbon nanotube defects friction