Computational Study Of Interficial Adhesion Between Carbon Nanotube And The Surfaces Of Cu, Cu₂O And Cu Nanowire

Since the discovery of carbon nanotubes (CNTs) by Iijima in 1991, CNTs have attracted great research interest due to their unique properties such as high electrical and thermal conductivity, excellent stiffness against bending, and high tensile strength. Using CNTs as nanofibers to enhance the mechanical, electrical, thermal, and optical properties of composite materials has been pursued extensively both in experimental and theoretical studies. Recently, experiments have shown remarkable enhancements in elastic modulus and strength of metal matrix with an addition of small amounts of CNTs. As well known, the interfacial adhension determine the properties of the CNT reinforced metal matrix composites. Therefore, it is significant to investigate the interficial adhesion for the practical application. As it is a challenge to study the interfacial adhesion mechanism in the experiment, the molecular mechanics and molecluar dynamic simulation are applied to solve the problem. This thesis try to investigate the interfacial adhension process, mechanism and the subsequent deformation of CNTs between CNTs and the surfaces of Cu, Cu2O and Cu nanowire.Firstly, force-field-based MD simulations are performed to study the interfacial adhesion of CNTs with different diameters, chiralities and walls to the surface of Cu and Cu2O. We analyse the interfacial properites, interfacial adhension mechanism and the influencing factors to adhesion energy between CNT and surfaces and examine the deformation of the CNTs. The surface Van der Walls force drives CNTs to approach and adhere to the surfaces, resulting in the collapse of the CNTs and the coverage of the collapsed CNTs on the surface like graphene ribbons. As the diameter size increases, the CNTs collapse easily, without the influence of the chiralites and other factors. Due to the large area contact induced by the collapse, the adhesions are strengthened and the stable heterogeneous structures are formed.In the MD simulation, we find that the surface Van der Walls force play the role in the in interfacial adhesion. So if we increae the specific surface area of the surface, the surface Van der Walls will be much stronger, the interfacial adhesion will tight and the deformation of the CNTs will much more serious. Therefore, we select a material with ever large specific surface area and study the interfacial adhesion. As well known, the copper nanowires are ideal one-dimensional materials, which possess large specific surface area. Subsequently, we study the interaction between CNTs and copper nanowires further in this work. When CNTs place beside the copper nanowires, they approach and adhere to each other. During the adhesion process, the CNTs collapse and cover on the copper nanowires like carbon nanosrolls, resulting the self-assembling of the core/shell nanowire structure. Based on the Lennard-Jones potential, we present a mechnical model to analyze the distribution of the force field around copper nanowires, which can demonstrate the formation of the copper nanowire/carbon nanoscrolls core/shell nanowires.The simulation resutes and the conclusions, which could decrease the research period and the cost on CNTs reinforced metal matrix composites, would be of great importance in the production of CNTs reinforced metal composites.