非公度双壁碳纳米管的层间摩擦

由于层间距和手性的耦合影响，非公度双壁碳纳米管的层间摩擦行为比较复杂，其规律至今仍不清楚。本文采用分子动力学模拟方法，研究了非公度双壁碳纳米管的层间摩擦特性。总体来说，层间距较小或层间手性角差较小时，层间摩擦力较大。当层间手性角差在10°以上时，层间接触接近非公度接触，层间摩擦力几乎不受层间手性影响；此时在层间平衡位置附近（0.34±0.02 nm），层间摩擦力与层间距之间近似呈线性关系。无论层间手性如何匹配，边界原子所受摩擦力总是大于内部原子所受摩擦力，显示边界效应是纳尺度摩擦中的一个普遍现象。

Interlayer Friction in Incommensurate Double Walled Carbon Nanotubes

Owing to the coupling effect between interlayer spacing and stacking angle, the interlayer friction in incommensurate double walled carbon nanotubes (DWCNTs) exhibits complex behavior and remains to be understood. Molecular dynamics simulation (MD) was applied in this paper to study the interlayer friction in incommensurate DWCNTs. In the calculations, the chiral angle of the outer tube was kept as 0° or 30°, while the chiral angle of the inner tube varied from 0°~30°. The results show that the interlayer friction is larger for smaller interlayer spacing or smaller difference in interlayer chiral angles. When the chiral angle difference is larger than 10° and the interlayer spacing is round 0.34 nm, the interlayer friction is linearly dependent on the interlayer spacing. The results show also that the friction force on edge atoms is significantly higher than that on inner atoms, indicating the edge effect is a general effect in nanoscale friction.