Micro structure analyses of nanotubes and their application to material science

本研究旨在阐明纳米管的微观结构及其在材料科学中的应用。为了达到这个目的，大量的纳米管是必需的。在这两年中，我们成功地获得了高质量的多壁碳纳米管和一定数量的单壁碳纳米管。它们在材料科学上的应用才刚刚开始。用纯石墨棒在纯氢气中进行直流电弧放电蒸发，可以得到高纵横比大于1000且高结晶的高质量纳米管。MWNTs的另一个特点是内管非常薄。最小的内管为0.4 nm，这是理论上期望的最小值。在拉曼光谱中，可以观察到与薄内管相对应的呼吸模式的峰值。目前正计划大量生产这种高质量的多壁纳米管。为了通过电弧放电获得大量的单壁碳纳米管，我们开发了一种倾斜电极的电弧等离子体方法。结果，在几分钟内获得了含有50%单壁碳纳米管的煤烟，其数量级为几克。该方法可用于实际应用，但单壁碳纳米管的提纯仍是一个有待解决的问题。

In this research, it was aimed to clarify the micro structure of nanotubes and their application to material science. For its purpose, a large amounts of nanotubes are necessary and required. In this two years, we have succeeded to get high quality multiwalled carbon nanotubes (MWNTs) and single-walled carbon nanotubes (SWNTs) in some quantity. Their application to material science has been just started.By DC arc discharge evaporation of pure graphite rod in pure hydrogen gas, high quality MWNTs of high aspect ratio larger than 1000 and highly crystarized ones could be obtained. Other characteristic feature of the MWNTs is that the inner tube is very thin. The smallest inner tube is 0.4 nm, which value is the smallest one theoretically expected. In Raman spectra, the peak of breathing modes corresponding to the thin inner tubes could be observed. Quantitative productions of such high quality MWNTs are planned now.In order to get a large quantity of SWNTs by arc discharge, we developed a new arc plasma method by inclining the electrode. As the result, soots including 50% SWNTs were obtained in the order of a few gram in a few minutes. It can be tested to practical application, but purification of SWNTs is still left problem.