水分子在不同碳纳米管中的结构和扩散研究

发布时间：2018-12-16 13:30

【摘要】：计算机模拟技术是一门涉及多种学科的新型科学技术，，并且已发展成为除理论研究与实验发现的第三大科学研究技术。分子动力学模拟正是基于计算机模拟技术的快速发展而形成的，分子动力学模拟可以为实验和理论研究提供大量可靠数据，弥补了实验和理论的不足之处，使广大科研工作者拥有了能够与世界先进科技接轨的研究技术。本文基于分子动力学模拟技术和碳纳米管特性，主要研究了在温度150K、300K、450K下水分子在不同碳纳米管中的的结构和扩散性质。通过改变碳纳米管的管径和温度，模拟了水分子在不同温度和不同管径下在碳纳米管中的结构，并计算了相应的扩散系数。本文中我们采用手扶椅型碳纳米管，水分子势能模型采用刚性的SPC势能模型。通过模拟我们发现水分子在温度为300K时，在(8,8)的碳纳米管中形成了规则的四边形结构，在温度为150K时，水分子没有规则的结构并且排列的有序度都降低；而在温度为150K和300K时，水分子在(9,9)、(10,10)、(11,11)的碳纳米管中都没有规则的结构，并且随着温度的升高水分子排列的有序程度有所降低。径向分布函数所对应的峰值随着碳纳米管管径的增大而逐渐增大，但径向分布函数所对应的波峰的峰位几乎不变，因此随着碳纳米管管径增大，水分子位置的分布会更加随机，即水分子的受限效应会减弱，此时大部分的水分子会分布在碳纳米管的管壁附近。在温度相同时，随着碳纳米管管径的增大，水分子的扩散系数逐渐增大；在同一管径中，随着温度的升高，水分子的扩散系数也逐渐增大。
[Abstract]:Computer simulation technology is a new science and technology involving many disciplines and has developed into the third largest scientific research technology in addition to theoretical research and experimental discovery. Molecular dynamics simulation is based on the rapid development of computer simulation technology. Molecular dynamics simulation can provide a large number of reliable data for experimental and theoretical research, and make up for the shortcomings of experiment and theory. So that the majority of scientific research workers have been able to connect with the world's advanced science and technology research technology. Based on the molecular dynamics simulation technique and the characteristics of carbon nanotubes (CNTs), the structure and diffusion properties of water molecules in different carbon nanotubes (CNTs) at 150K ~ 300K ~ 450K have been studied in this paper. By changing the diameter and temperature of carbon nanotubes, the structure of water molecules in carbon nanotubes at different temperatures and diameters was simulated, and the corresponding diffusion coefficients were calculated. In this paper, we adopt the armchair type carbon nanotubes and the water molecular potential energy model using the rigid SPC potential energy model. Through simulation we found that water molecules formed regular quadrilateral structure in (8 ~ 8) carbon nanotubes at the temperature of 300K, and at the temperature of 150K, the water molecules had no regular structure and the order degree of the arrangement decreased. At temperatures of 150K and 300K, there is no regular structure of water molecules in carbon nanotubes (9 9), (1010), (1111), and the order degree of water molecules decreases with the increase of temperature. The peak value of radial distribution function increases gradually with the increase of diameter of carbon nanotubes, but the peak position of wave peak corresponding to radial distribution function is almost unchanged, so the distribution of water molecular position is more random with the increase of diameter of carbon nanotubes. In other words, the limiting effect of water molecules will be weakened, and most of the water molecules will be distributed near the wall of carbon nanotubes. At the same temperature, the diffusion coefficient of water molecules increases with the increase of the diameter of carbon nanotubes, and the diffusion coefficient of water molecules increases with the increase of temperature in the same tube diameter.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O613.71

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