Collaborative Research: Scalable Separation of Single Walled Carbon Nanotubes

Pfefferle/Frey 1264698/1264698 PI提出了一种新的方法来对SWNT进行可扩展的手性分离，其中将手性确定的表面电荷引入到SWNT上;随后，采用液相色谱技术来解析单个SWNT亚型。制备用于后续分离的单壁碳纳米管的化学处理程序涉及以利用不同手性反应性的方式将官能团应用于纳米管。这又导致官能化纳米管亚型的不同表面酸性/碱性，如它们不同的零电荷点（PZC）值所反映的。Pfefferle教授是单壁碳纳米管合成和生产单壁碳纳米管特性的窄分布以及功能化和表征它们的专家。她还开发了使用SWNT表面电荷作为手性标记的概念。功能化的单壁碳纳米管将被分离的基础上，其表面电荷使用高分辨率，高通量的方法，涉及色谱聚焦，利用静电相互作用。在过去的几年里，UMBC的Frey博士一直在开发这种类型的方法，用于生物技术应用，并将在这里进一步调整，以便它们特别适用于SWNT分离的情况。为了实现这一目标，PI将研究使用柱填充材料，这些材料可能会提高单壁碳纳米管的吸附能力，例如触手型柱填充，其中离子交换官能团位于从颗粒表面向外延伸的线性聚合物链上。PI还将研究创新洗脱策略的使用，包括色谱聚焦结合移动的相改性剂，优化洗脱期间静电力和疏水力之间的平衡。另一条调查线将是评估新的方法来影响单壁碳纳米管的行为在色谱法，如使用微波辐射。 更广泛的影响：该研究的预期结果将是一种灵活的方法，可以从实验室规模到工业规模生产纯化的SWNT亚型。采用混合批次的SWNT并以可扩展的方式获得每种组分的高度选择性分离的能力是碳纳米管领域的重要目标。目前无法获得廉价的高纯度单壁碳纳米管是基于单壁碳纳米管的电子学至今尚未实用的主要原因。通过解决这一关键的技术挑战，该项目有可能成为真正的变革。尽管它们具有深远的潜力，这里要研究的方法在概念上很简单，并且很好地适用于涉及本科生和高中生的项目。许多这样的学生参加了过去的PI？耶鲁大学和UMBC的研究。 PI将扩大这一努力，包括我们的团体之间的互动，从而为各级学生提供了一个特殊的机会，让他们参与利用PI互补能力的跨学科研究计划。

Pfefferle/Frey1264698 / 1264698The PIs propose a novel approach to the scalable, chiral separation of SWNT in which chirality-determined surface charge is introduced onto the SWNT; subsequently, liquid chromatography techniques are employed to resolve individual SWNT subtypes. The chemical processing procedures which prepare the SWNT for subsequent separation involve the application of functional groups to the nanotubes in a way that exploits differential chiral reactivity. This in turn leads to differential surface acidity/basicity for the functionalized nanotube subtypes as reflected in their different point of zero charge (PZC) values. Professor Pfefferle is an expert in SWNT synthesis and in producing narrow distributions of SWNT identities and functionalizing and characterizing them. She is also developing the concept of using SWNT surface charge as a chirality marker. Functionalized SWNT will be separated on the basis of their surface charge using high-resolution, high-throughput methods involving chromatofocusing that exploit electrostatic interactions. Methods of this type have been under development over the last several years by Dr. Frey at the UMBC for biotechnology applications and will be further adapted here so that they apply specifically to the case of SWNT separations. To accomplish this, the PIs will investigate the use of column packing materials that are likely to enhance the adsorption capacity for SWNT, such as tentacle-type column packings, where the ion-exchange functional groups are located on linear polymer chains extending outward from the particle surface. The PIs will also investigate the use of innovative elution strategies involving chromatofocusing focusing in combination with mobile phase modifiers that optimize the balance between electrostatic and hydrophobic forces during elution. Another line of investigation will be to evaluate novel methods to affect the behavior of SWNT during chromatography, such as the use of microwave radiation. Broader Impacts: The expected result of the proposed research will be a flexible method that can produce subtypes of purified SWNT from the laboratory scale to the industrial scale. The ability to take a mixed batch of SWNT and, in a scalable manner, obtain a highly selective separation of each component is an important goal in the carbon nanotube field. The current unavailability of inexpensive high purity SWNT is the major reason why SWNT-based electronics have not been practical to-date. By solving this key technical challenge, this project has the potential to be truly transformative. Despite their far-reaching potential, the methods to be investigated here are simple in concept and lend themselves well to projects involving both undergraduate and high school students. Many such students have participated in the past in the PIs? research both at Yale and UMBC. The PIs will expand this effort and include interactions between our groups, and thereby present an exceptional opportunity for students at all levels to participate in an interdisciplinary research program that exploits the complementary capabilities of the PIs.