Selective dipersion of single-walled carbon nanotubes with conjugated polymers

碳纳米管是一种独特的材料，完全由碳原子组成，碳原子结合在一个以圆柱体形状排列的铁丝网框架中。除了它们迷人的结构特性外，它们还表现出从金属到半导体的导电性，使它们适用于许多电子设备。不幸的是，所有制备单壁碳纳米管（SWNTs）的方法都会产生半导体和金属结构的混合物，这使得它们很难应用于需要一种或另一种纯样品的电子设备中。因此，根据碳纳米管的电导率进行大规模分离是碳纳米管在商业产品中充分发挥其潜力之前必须克服的主要问题。所有已知的纳米管分离方法，包括密度梯度超离心、凝胶过滤和电泳，都只能在很小的范围内进行分离，而且成本很高。然而，最近的研究结果表明，富电子共轭聚合物可以选择性地与半导体单壁碳纳米管相互作用，并在各种溶剂中分散。不幸的是，这种相互作用中选择性的基本原理尚不清楚，而且金属纳米管以前也没有被共轭聚合物选择性地分散。该提案将进一步研究导致与金属或半导体SWNTs相互作用选择性的聚合物属性，并将确定一组可用于实现所需纳米管的高效，大规模分离的聚合物。这项工作将与生产和销售碳纳米管的加拿大公司雷莫工业公司合作进行。该公司对开发纯化和分离单壁碳纳米管的新方法非常感兴趣。因此，该项目将揭示共轭聚合物与不同类型的SWNTs之间选择性相互作用的基本基础，并将提供具有商业意义的材料。

Carbon nanotubes are a unique material composed entirely of carbon atoms bonded in a chicken-wire framework that is arranged in the shape of cylinders. In addition to their fascinating structural properties, they exhibit electrical conductivity properties that range from metallic to semiconducting, making them applicable to a number of electronic devices. Unfortunately, all methods to prepare single-walled carbon nanotubes (SWNTs) produce a mixture of both semiconducting and metallic structures, making it difficult to apply them in electronic devices that require pure samples of one type or the other. Thus, bulk-scale separation of carbon nanotubes according to their conductivity properties is a major problem that must be overcome before SWNTs can reach their full potential in commercial products. All known methods for separation of nanotubes, including density-gradient ultracentrifugation, gel filtration, and electrophoresis, result in separation on very small scale, and are achieved at high cost. However, recent results have demonstrated that electron-rich conjugated polymers can selectively interact with and disperse semiconducting SWNTs in various solvents. Unfortunately, the fundamentals of selectivity in this interaction are not understood, and metallic nanotubes have not previously been shown to be selectively dispersed by conjugated polymers. This proposal will further investigate the polymer attributes that lead to interaction selectivity with either metallic or semiconducting SWNTs, and will identify a set of polymers that can be used to achieve highly efficient, large-scale separation of the desired nanotubes. This work will be carried out in collaboration with Raymor Industries, a Canadian company that produces and sells SWNTs. This company is extremely interested in developing new ways to purify and separate SWNTs. Thus, this project will uncover fundamental underpinning of the selective interaction between conjugated polymers and different types of SWNTs, and will provide materials that are of commercial significance.