纳米材料的电致形变及力学性能研究

发布时间：2018-01-14 13:26

本文关键词：纳米材料的电致形变及力学性能研究　出处：《南京大学》2017年博士论文　论文类型：学位论文

【摘要】：近年来,纳米材料的力学及电学特性受到人们越来越多的关注。该材料力学和电学性能的数值计算,理论模拟和实验检测的研究是材料学领域非常重要的课题之一。由于纳米材料具有尺寸小,结构缺陷和制样困难的问题,现阶段对其特性的研究仍然存在很大难度。本文立足于这一研究背景,致力于运用明场,相差和表面等离子体显微成像技术来研究纳米尺度下的材料微观力学和电学性能。主要内容如下:1.Pauli斥力引起的单层石墨烯拉伸及电力学特性石墨烯独特的二维结构使其具有很多方面的特性,并且吸引了越来越多研究者们的关注。但是压电性能的缺乏使得它在电力学方面的应用受到了限制。由于单层石墨烯在狄拉克点具有零态密度,对石墨烯充电必须克服Pauli排斥力。我们运用光学边缘跟踪的方法对斥力引起的石墨烯边缘拉伸现象进行了测量。Pauli斥力引起石墨烯边缘拉伸这一发现提供了一种电学控制石墨烯维度的方法。光学边缘跟踪法和显微镜成像技术的结合提供了一种研究石墨烯的弹性性质和其它低维度材料的力学特性的简单且直接的方法。2.单纳米线电化学表面应力的测定纳米材料具有较大的表面积-体积比,使其在力学性能和电催化性能上显示了极大的优势。因此,这些材料的电化学表面应力研究有着十分重要的意义。但是到目前为止,对单个纳米材料电化学表面应力的研究存在较大难度。我们将边缘跟踪法和光学显微镜技术相结合,第一次原位测定了单根金纳米线的电化学过程导致的表面应力变化过程。对电压求导后的表面应力曲线的形状与传统电化学方法测得的循环伏安曲线相似。我们认为这些观察到的现象是由金纳米线表面的阴离子吸附和氧化/还原过程引起的。这一工作为研究低维度纳米材料的电化学过程和相应的表面应力变化提供了一种全新的研究手段。3.单纳米粒子碰撞过程的瞬态研究我们运用基于表面等离子体共振技术的光学显微镜对单纳米粒子和基底之间的碰撞过程进行了成像研究。通过理论模拟和实验结果的比较,我们可以得到不同纳米粒子的碰撞动力学过程,从而表征单个纳米材料的特性以及与基底之间的效应。该研究在单分子检测和缺陷表征领域中拥有极大的发展前景。
[Abstract]:In recent years, more and more attention has been paid to the mechanical and electrical properties of nanomaterials. The research of theoretical simulation and experimental testing is one of the most important topics in the field of materials science. Due to the small size of nanomaterials, structural defects and difficulties in sample preparation. At present, the study of its characteristics is still very difficult. This paper is based on this research background, committed to the use of open field. Phase contrast and surface plasma microimaging techniques are used to study the micromechanical and electrical properties of nanoscale materials. The main contents are as follows:. 1. The tensile and electrical properties of graphene monolayer induced by Pauli repulsion; graphene has many properties due to its unique two-dimensional structure. It has attracted more and more researchers' attention, but its application in electricity is limited by the lack of piezoelectric properties. Because of the zero state density of graphene monolayer at Dirac point. The Pauli repulsive force must be overcome for graphene charging. We use the method of optical edge tracking to measure the graphene edge stretching phenomenon caused by repulsion force. Pauli repulsion force causes graphene edge stretching. The combination of optical edge tracking and microscopic imaging provides a simple way to study the elastic properties of graphene and the mechanical properties of other low-dimensional materials. And the direct method .2. the single nanowire electrochemical surface stress measurement nanomaterials have a large surface area to volume ratio. Therefore, the study of electrochemical surface stress of these materials is of great significance. But up to now, it is very important to study the electrochemical surface stress of these materials. It is difficult to study the electrochemical surface stress of a single nanomaterial. We combine the edge tracking method with the optical microscope technique. The change of surface stress induced by electrochemical process of a single Jinnanmi wire has been measured in situ for the first time. The shape of the surface stress curve after the voltage derivation is similar to the cyclic voltammetry curve obtained by the traditional electrochemical method. It is considered that these observed phenomena are caused by the anion adsorption and oxidation / reduction process on the surface of the nanowires. This work provides a useful method for studying the electrochemical process and the corresponding surface stress changes of the low-dimensional nanomaterials. Transient study on the collision process of single nanoparticles We used an optical microscope based on surface plasmon resonance (SPR) technique to study the collision process between a single nanoparticles and a substrate. The results of theoretical simulation and experiment are compared. The collision dynamics of different nanoparticles can be obtained. Therefore, the properties of single nanomaterials and the effect between them and the substrate are characterized. This research has great prospects in the field of single molecule detection and defect characterization.
【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TB383.1

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