高温加热单壁碳纳米管的分子动力学研究

Molecular Dynamics Simulations of Heating up the Single-walled Carbon Nanotube at High Temperature

运用紧束缚分子动力学方法,模拟了单壁碳纳米管(SWCNT)在真空中高温受热形变直至破裂的过程。为研究不同手性角对碳纳米管性能的影响,选取半径相近、长度相同的(5,5)扶手椅型碳纳米管和(9,0)锯齿型碳纳米管进行模拟,两者的手性角分别为30°和0°。结果表明,扶手椅型碳管比锯齿型碳管具有更好的热稳定性和耐高温性。(9,0)锯齿型碳管在4700 K左右就开始破裂,而(5,5)扶手椅型碳管在5400 K左右才开始破裂。另外在高温下扶手椅型碳管的端口比锯齿型碳管的更易封闭,这可能意味着它们具有不同的生长方式。封口有助于减少端口的悬挂健,降低体系的能量。

We use the tight-binding molecular dynamics simulation, explore the distortion of single-waUed nanotubes when being heated up at high temperature in the vacuum. In order to study different properties of carbon nanotube with the different chair angles, （5,5） armchair tube and zigzag （9,0） tube with the similar radius and same length are selected to simulate. Their chair angles are 30° and 0° separately. The results suggest that armchair carbon nanotube is more heat-resistant than zigzag. （9,0） zigzag tube begins to crack at 4700 K, while （5,5） armchair tube happens at 5400 K. Moreover, the ends of （5,5） armchair close easier than those of （9,0） zigzag when being heated up at high temperature, which might mean their growth with different model. The closing of the ends decreases the growth of the system energy by reducing the hanging bonds. Correspondingly the bond theory provides some explanation to the results. The research will be helpful to study CNT growth and their application.