【作者】 张毅；

【导师】 王万录； 廖克俊；

【作者基本信息】 重庆大学 ， 凝聚态物理， 2005， 硕士

【摘要】 自从1991 年碳纳米管被发现以来,它就引起了研究人员的极大兴趣,原因不仅是因为碳纳米管所具有的独特力学和电学特性,还因为碳纳米管有很多有待发现的新特性。在寻找可用于特殊环境下,基于碳纳米管的传感器件的可能应用中,我们发现了碳纳米管膜压阻效应的应用可能。本文首先简要介绍了碳纳米管材料当前的研究状况,其独特的性质和应用潜力。其次我们介绍了碳纳米管的合成方法,着重介绍了CVD 法合成碳纳米管的各种工艺条件和试验结果,讨论了碳纳米管的生长机理。碳纳米管的力学性质是本文论述的重点之一。首先我们从碳纳米管的结构、实验、应用等几个方面,对以往的各类实验进行了总结,着重讨论了碳纳米管的一些特殊的力学行为。其次根据对碳纳米管结构的分析,阐述了它奇异特性的产生原因;最后简要的讨论了碳纳米管的一些力学方面的应用前景。碳纳米管的压阻效应是本文论述的重点之二。与压电效应不同,压阻效应是在外力作用下电阻的变化.压阻因子是在单位应变下电阻的相对改变,是材料的压阻效应的量度。我们对压阻因子进行了介绍与讨论。本文利用弯曲法研究了碳纳米管膜的压阻效应。实验结果表明碳纳米管膜有显著的压阻效应。最后讨论了碳纳米管膜形成压阻效应的原因。碳纳米管压阻效应的应用研究是本文讨论的重点之三。我们对多壁碳纳米管膜在高速转动下的压阻效应进行了研究,并讨论了利用这种效应来测量转动速度和制造这类传感器的可能性。实验研究发现:在室温下,多壁碳纳米管膜的电阻随转子转速的增加而增加,在转子转速从1000r/min—3000r/min 的变化过程中,多壁碳纳米管膜的电阻近似成线性变化。并且碳纳米管膜在拉伸和压缩两种情况下电阻变化与转速之间的关系曲线近似对称。更多还原

【Abstract】 Since their discovery in 1991, carbon nanotubes (CNTs) have attracted interest not only for their unusual mechanical and electrical properties, but also for their properties which have not been discovered. In the course of investigation of possible applications of CNT-based sensors for special environment, we have found the piezoresistivity in CNT films. The state of the art of current research for carbon nanotube materials and their ability for field emitters and other devices are reviewed at first. Carbon nanotube and their synthesis methods were studied. Single-walled and multi-walled carbon nanotube ware synthesized by chemical vapor deposition(CVD). The influence of some factors on growth of CNT were investigated. This paper overviewed the mechanical behaviors and its related experiments and properties of carbon nanotube, one of most important nano-materials which urgently neets research and application. From the aspect of structure ,experiment and application, the paper emphatically summarized kinds of experiments and comments on some unusual mechanical behaviors of carbon nanotube. According to the structural analysis of carbon nanotube, the paper explain the causes of these peculiar performances. By way of molecular dynamics simulation, it also analyzed some mechanical and electronic properties of carbon nanotube. At last, this paper summarized some future prospective application of carbon nanotube in mechanical realm. Difference from piezoelectricity, piezoresistivity is the change in resistance when mechanical force is applied. The gauge factor, which is the relative change in resistance per unit strain, is a measure of a material piezoresistivity. We introduced the gauge factor particularly. In this Paper, the piezoresistive effect of carbon nanotube films was investigated by bending method. The carbon nanotubes used in this study were synthesized by hot filament chemical vapor deposition. The experimental results showed that there has a striking piezoresistive effect in carbon nanotube films. The piezoresistive effect of the mutiwall carbon nanotube films at high rotational speed has been studied, the possibility as a sensor to measure the rotational speed also has been discussed. It is found that the resistance of the MWCNT films increases with the increasing of the rotational speed at room temperature. The resisrance increase nearly linearly with the speed from 1000r/min—3000r/min. The relation curves of the resistance changes of MWCNTs under tensile and compressed stress were approximately symmetrical.更多还原