Short [N,N] Carbon Nanotubes of Uniform Diameter by Chemical Synthesis and Tests of Methods for Their Elongation

该项目的长期目标是开发方法，通过化学合成获得有用数量的均匀直径的单壁碳纳米管，所有这些碳纳米管都具有相同的侧壁结构。具有n = m的[n，m]指数的碳纳米管（CNT），即所谓的扶手椅型CNT，已被选为初始目标，因为它们都是导电的（金属的），因此可以用作分子尺度器件中的纳米线。总体策略开始于短的半球形烃纳米管的自下而上的化学合成，并以其伸长为全长CNT而达到高潮;短烃模板中编码的直径和边缘结构将决定所得纳米管的直径和侧壁结构（[n，m]指数）。 美国国家科学基金会的化学合成计划支持波士顿学院的Lawrence Scott教授合成[5，5]，[6，6]和[10，10] CNT，并与Robert C.位于滨江的加州大学的Haddon博士的论文，以测试这种模板的伸长的方法。 预期由这种生长过程导致的尺寸的巨大放大使得可从甚至毫克量的小烃模板获得有用量的均匀直径扶手椅型CNT。1991年碳纳米管的发现几乎立即激发了科学家和工程师的梦想，这些重量轻，超强，耐热，超薄的纳米线可以彻底改变电子设备的小型化，远远超过目前在硅芯片上光刻所能实现的。不幸的是，并非所有的碳纳米管（CNT）都是一样的。有些是半导体，而另一些则是高导电性的，如金属，其载流量比铜线大1000倍。然而，尽管在世界范围内进行了二十年的广泛实验，但所有已知的制备方法仍然产生不同类型的CNT的混合物，这些混合物实际上不可能以有用的量分离成它们的单独组分。显然需要更多的控制方法来合成预定尺寸和化学结构的CNT，本项目的重点是开发这种方法。这一跨学科项目为研究生和本科生（包括妇女）以及一名博士后研究员提供研究培训。此外，多位博士最近，来自瑞士、日本、台湾和澳大利亚的学生，都获得了来自本国的奖学金，来到斯科特教授的实验室，合作进行这个项目，为期三到十二个月。 该项目的互动和多样化的研究环境为培训和学习以及发展一支更强大的、具有科学和文化素养的劳动力队伍提供了一个极好的环境。更广泛的影响还包括通过出版物和在国家和国际会议上的演讲传播研究成果。

The long term objective of this project is the development of methods to access useful quantities of uniform diameter, single-walled carbon nanotubes, all having identical sidewall structures, by chemical synthesis. Carbon nanotubes (CNTs) having [n,m] indices with n = m, the so called armchair CNTs, have been chosen as the initial objectives, because they will all be electrically conductive (metallic) and can therefore serve as nanowires in molecular scale devices. The overall strategy begins with bottom-up chemical syntheses of short, hemispherical hydrocarbon nanotubes and culminates with their elongation to full length CNTs; the diameter and rim structure encoded in the short hydrocarbon templates will dictate the diameter and sidewall structure (the [n,m] index) of the resulting nanotubes. The Chemical Synthesis Program of the National Science Foundation supports Professor Lawrence Scott of Boston College to synthesize [5,5], [6,6], and [10,10] CNTs and, in collaboration with Professor Robert C. Haddon of the University of California at Riverside, to test methods for the elongation of such templates. The enormous amplification in size resulting from such growth processes is anticipated to make useful amounts of uniform diameter armchair CNTs available from even milligram quantities of the small hydrocarbon templates. The discovery of carbon nanotubes in 1991 almost instantly inspired dreams among scientists and engineers about how these light weight, super strong, heat resistant, ultra thin nanowires could revolutionize the miniaturization of electronic devices far beyond what can currently be achieved by lithography on silicon chips. Unfortunately, not all carbon nanotubes (CNTs) are alike. Some are semiconductors, whereas others are highly conductive, like metals, with current carrying capacities up to 1000 times greater than that of copper wire. Despite two decades of extensive experimentation worldwide, however, all known preparation methods still yield mixtures of different types of CNTs that are virtually impossible to separate into their individual components in useful amounts. More controlled methods for synthesizing CNTs of predefined dimensions and chemical structure are clearly needed, and this project is focused on the development of such methods. This interdisciplinary project provides research training to graduate and undergraduate students (including women) and a postdoctoral researcher. In addition, several Ph.D. students who have won fellowships from their home countries have recently come to the laboratory of Professor Scott from Switzerland, Japan, Taiwan, and Australia to collaborate on this project for periods of three to twelve months each. The interactive and diverse research environment of this project provides an excellent setting for training and learning and for the development of a stronger, scientifically and culturally literate workforce. The broader impacts also involve disseminating research results through publications and presentations at national and international conferences.