Department of Civil Engineering, Monash University, Clayton, Victoria, Australia 3800.
ACS Nano. 2010 Apr 27;4(4):2338-44. doi: 10.1021/nn1001694.
Transportation of water molecules in a carbon nanotube based on an energy pump concept is investigated by molecular dynamics simulations. A small portion of the initially twisted wall of a carbon nanotube is employed to function as an energy pump for possible smooth transportation of water molecules. The momentum and resultant force on a water molecule and the corresponding displacement and velocity of the molecule are particularly studied to disclose the transportation process. The efficiency of the transportation is found to be dependent on the size of the energy pump. Once the process for the transportation of one molecule is elucidated, transportations of 20 water molecules are simulated to investigate the effect of the environmental temperature and fluctuations in the nanotube channel on the transportation. It is revealed that the accelerated period of multiple water molecules is longer than that in the transportation of a single water molecule. In addition, the fluctuations in the nanotube wall due to the buckling propagation and a higher environmental temperature will all lead to obvious decreases in the water velocity and hence retard the transportation process.
基于能量泵概念的水分子在碳纳米管中的输运通过分子动力学模拟进行了研究。利用初始扭曲碳纳米管壁的一小部分作为能量泵，以实现水分子的平滑输运。特别研究了水分子的动量和由此产生的力以及分子的相应位移和速度，以揭示输运过程。发现输运效率取决于能量泵的大小。一旦阐明了单个分子的输运过程，就模拟了 20 个水分子的输运，以研究环境温度和纳米管通道中的波动对输运的影响。结果表明，多个水分子的加速期比单个水分子的输运期长。此外，由于屈曲传播和较高环境温度导致的纳米管壁的波动都会导致水分子速度明显降低，从而减缓输运过程。
