Filled and empty states of carbon nanotubes in water: Dependence on nanotube diameter, wall thickness and dispersion interactions
Filled and empty states of carbon nanotubes in water: Dependence on nanotube diameter, wall thickness and dispersion interactions
复制标题
碳纳米管在水中的填充和空态：取决于纳米管直径、壁厚和分散相互作用
DOI：
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
A. Chandra
中科院分区：
文献类型：
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作者：
M. Rana;A. Chandra
我们对含有窄碳纳米管作为溶质的水进行了一系列分子动力学模拟，以研究纳米管的填充和排空，以及纳米管内部和外表面附近水的密度和氢键分布的变化。我们的主要目标是观察不同的纳米管直径、壁厚以及溶质-溶剂相互作用对溶质外表面附近受限区域内溶剂结构的影响。通过考虑单壁和多壁纳米管来改变壁厚，通过调整碳原子和水分子之间的12-6对相互作用势的吸引强度来改变相互作用势。计算完成了许多不同的调谐参数值，从完全的伦纳德-琼斯到纯排斥对相互作用。研究发现，溶质-水相互作用势中吸引部分的强度对溶质-水的溶剂化特性和氢键分布都有很大的影响。然而，纳米管壁厚度对密度分布、氢键网络和润湿特性的影响很小。这表明纳米管内部和外部水分子之间的远距离静电相互作用对这些疏水溶质的整体溶剂化结构没有任何显著贡献。溶剂化特性主要取决于氢键网络破坏造成的能量损失、空腔斥力和溶质-水相互作用的吸引分量所抵消的能量损失之间的平衡。我们对不同体系尺寸的研究表明，不同直径和相互作用势的窄纳米管在大约500个分子组成的相对较小的体系中也存在润湿和脱湿的基本特征。
We have carried out a series of molecular dynamics simulations of water containing a narrow carbon nanotube as a solute to investigate the filling and emptying of the nanotube and also the modifications of the density and hydrogen bond distributions of water inside and also in the vicinity of the outer surfaces of the nanotube. Our primary goal is to look at the effects of varying nanotube diameter, wall thickness and also solute-solvent interactions on the solvent structure in the confined region also near the outer surfaces of the solute. The thickness of the walls is varied by considering single and multi-walled nanotubes and the interaction potential is varied by tuning the attractive strength of the 12–6 pair interaction potential between a carbon atom of the nanotubes and a water molecule. The calculations are done for many different values of the tuning parameter ranging from fully Lennard-Jones to pure repulsive pair interactions. It is found that both the solvation characteristics and hydrogen bond distributions can depend rather strongly on the strength of the attractive part of the solute-water interaction potential. The thickness of the nanotube wall, however, is found to have only minor effects on the density profiles, hydrogen bond network and the wetting characteristics. This indicates that the long range electrostatic interactions between water molecules inside and on the outer side of the nanotube do not make any significant contribution to the overall solvation structure of these hydrophobic solutes. The solvation characteristics are primarily determined by the balance between the loss of energy due to hydrogen bond network disruption, cavity repulsion potential and offset of the same by attractive component of the solute-water interactions. Our studies with different system sizes show that the essential features of wetting and dewetting characteristics of narrow nanotubes for different diameter and interaction potentials are also present in relatively smaller systems consisting of about five hundred molecules.
影响因子：
3.4
作者：
Zhu, FQ;Schulten, K
通讯作者：
Schulten, K