正二十六烷烃填充碳纳米管复合体系的结构及其扩散的分子动力学模拟研究  

Molecular Dynamics Simulation of Structure and Diffusion of n-Hexacosane Molecules Confined in Carbon Nanotubes

作　　者：李新芳[1] 吴淑英[2] 

机构地区：[1]中山火炬职业技术学院,中山528436 [2]湘潭大学机械工程学院,湘潭411105

出　　处：《真空科学与技术学报》2017年第8期836-840,共5页Chinese Journal of Vacuum Science and Technology

基　　金：广东省科技计划项目(2016A010104002);广东省高等学校优秀青年教师培养计划项目(Yq2013197);国家自然科学基金项目(51206071)

摘　　要：采用分子动力学方法,研究了正二十六烷烃体系和正二十六烷烃填充碳纳米管(CNTs)复合体系的微观结构和扩散性质。研究表明:两种体系的有序性均随着温度的升高而逐渐降低,液态时的有序性均低于固态。正二十六烷烃分子在CNTs管内与在自由态下杂乱无章的结构相比,正二十六烷烃分子在CNTs管内呈有序的环状分布,且管内烷烃分子的有序度高于自由态,自扩散系数也高于自由态。烷烃分子进入CNTs管内后,其熔化温度比自由态的低4.1℃,与实验结果一致。高有序性和CNTs对烷烃分子的限制作用是导致CNTs管内填充有机相变材料相变温度降低的重要原因。The atomic structure and diffusion of n-hexacosane in free-and confined statesinside carbon nanotubes（ CNT） were mathematically modeled,numerically simulated in molecular dynamics with software Materials studio. The impact of the temperature and phases on the orderedness inside CNTs and diffusion was investigated.The simulated results show that depending on the temperature,CNT confinement significantly affects the orderedness,melting point and diffusion of n-hexacosane molecule. To be specific,as the temperature increases,the orderedness of n-hexacosane molecule in free-and confined states strongly decreases,and a considerable decrease of the orderedness occurs in solid-liquid transition. CNT confinement completely turns the randomly ordered n-hexacosane molecule in free-state into the highly ordered one conformal with CNT＇s wall,significantly increases the self-diffusion coefficient,and sharply decreases the melting temperature by 4. 1℃. The simulated and reported resultswere in good agreement.

关 键 词：正二十六烷烃填充碳纳米管 微观结构 扩散系数 分子动力学 

分 类 号：TK124[动力工程及工程热物理—工程热物理]