石墨基底上金属纳米薄膜去湿和脱附的分子动力学研究

发布时间：2018-01-05 22:34

本文关键词：石墨基底上金属纳米薄膜去湿和脱附的分子动力学研究　出处：《湘潭大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前,固态基底上薄膜的去湿润行为已经得到了广泛的理论和实验研究,得到了许多有意义的研究结果。而不同的薄膜材料,如水分子,高分子聚合物,金属等,由于不同的原子结合特征和表面特性,其去湿润行为表现出了明显的差异。金属薄膜因其具有高表面能,低粘性系数,长程相互作用力等特点使其在固态基底表面动力学演化的去湿润和脱离行为明显不同于水分子和高分子有机聚合物等软物质材料。一般来讲,纳米薄膜在固态基底表面的动力学演化过程不仅与环境的温度和压力等因素有关,而且与纳米薄膜的厚度,尺寸,甚至形状等参数也有关。近年来,探讨纳米薄膜的去湿润行为与这些因素的依赖关系是纳米材料研究领域的热点问题。本文采用分子动力学的方法研究了金属Pt纳米薄膜在固态石墨基底表面的动力学演化过程。通过构建石墨基底上不同层数的金属Pt圆盘纳米薄膜,探讨金属纳米薄膜在固态基底表面的去湿以及脱附的动力学演化过程对薄膜初始厚度、温度以及基底层数等的依赖关系。我们的研究结果表明,在一定的温度条件下,不同初始厚度的Pt纳米薄膜存在不同的去湿现象。由于Pt原子层和石墨基底之间有较强的相互作用,层数较小的纳米薄膜在去湿过程中会形成纳米空洞,并且完全脱离基底表面需要较高的温度;而层数较大的纳米薄膜的去湿过程则从薄膜边缘开始收缩,直到最终形成纳米液滴,以一定的速度脱离基底表面。进一步的研究表明,随着金属纳米薄膜初始层数的增加,液滴脱离基底表面的速度先增大后减小,这一结果我们通过去湿过程中金属的表面能和金属与基底之间的相互作用能之间的竞争关系进行了理论分析。此外,我们还通过比较Au和Pt的圆盘纳米薄膜的去湿和脱附过程,探究金属薄膜与基底间的粘滞耗散对液膜去湿的影响。这些研究结果不仅对于理解其他金属纳米薄膜在固态基底表面的动力学演化过程具有理论意义,而且对于金属镀膜,表面清洁,器件表面去湿等工业生产过程具有一定的现实意义。
[Abstract]:At present, the film on the solid substrate to wet behavior has been extensive theoretical and experimental research, obtained many significant research results. But the different film materials, such as water molecules, polymers, metals, due to the different atomic binding characteristics and surface properties, the wetting behavior to show obvious because of the differences. The metal film with high surface energy, low viscosity, long range interaction characteristics in the evolution of the surface of the solid substrate to the dynamics of wetting and detachment act is different from the water molecules and the polymer polymer soft materials. Generally speaking, the evolution of nano film dynamics in the surface of the solid substrate process not only with the environment factors such as temperature and pressure, and the nano film thickness, size, and shape parameters are also relevant. In recent years, to investigate the nano thin film to wet line As a dependent relationship with these factors is a hot topic in the research field of nano materials. In this paper, by the method of molecular dynamics study of metal Pt nano films in the evolution kinetics of solid state graphite substrate surface. By constructing the graphite substrate of different layers of metal nano film thickness of Pt disc, the desorption kinetics of metal nano film on solid substrate the surface of the wet and the evolution process of the initial film, temperature dependence and substrate layers. Our results show that under certain temperature conditions, Pt nano films with different initial thickness of different dewetting. Due to the strong interaction between Pt atom layer and the graphite substrate, nano thin film layers the smaller will form nano void in the dewetting process, and completely detached from the substrate surface requires high temperature and large number of nanometer thin films; The dewetting process from the film edge began to shrink, until the final formation of nano droplets, to a certain speed from the surface of the substrate. Further research showed that with the increase of the initial number of nanometer metal film, droplet detachment surface velocity increases first and then decreases, the results we go by the competition between the interaction between surface in the process of wet metal and metal substrate can be analyzed. In addition, we also compared Au nano film through the disk and Pt to wet and desorption process, effects of viscous dissipation of metal between the film and substrate of the film to wet. These results not only for the understanding of other metals nano film evolution dynamics in the surface of the solid substrate process has theoretical significance, but also for the metal coating, surface cleaning, surface of the device to damp the industrial production process has a certain current Real meaning.

【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383

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