CAREER: Synthesis, Characterization, and Applications of Cyclic Polymer "Nanoloops"

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。技术摘要：通过使用高效反应偶联聚合物链？S头和尾，本研究项目为制备环状聚合物提供了一条通用的途径。由于以前合成路线的各种合成和技术限制，环状聚合物的许多基本性质仍存在争议，其潜在应用仍未得到充分探索。所开发的环化方法是强大的，因为它可以提供高纯度的环聚合物，同时也提供了具有相同分子量分布的线性类似物。因此，循环拓扑对聚合物物理性质的影响将在各种研究中进行探讨，包括热行为、流变学、降解行为、小角度x射线散射和抗菌活性。此外，聚合和环化化学的官能团耐受性使得可以通过连接线性或枝状聚合物侧链进一步修饰一系列功能环骨架。这些杂化结构特别令人感兴趣，因为模块化合成可以控制环状聚合物的尺寸，刚度和功能。它们的物理性质和封装纳米材料（如巴克球、量子点和单壁纳米管）的能力将作为这些变量的函数进行探索。本研究的首要目标是对环状聚合物结构如何影响这类大分子的相互作用和物理性质有一个更好的基本理解。非技术概述：环状大分子，包括质粒DNA和许多生物相关肽，在自然界中是众所周知的，并且由于其圆形拓扑结构而表现出独特的性质和相互作用。然而，高效制备合成聚合物纳米环的能力？相对于线性聚合物的先进合成控制演示，已经明显滞后。使用有效的？头对尾？偶联技术，可以获得高纯度的环状聚合物，以探索这些合成大分子的基本性质和潜在的有用性质。特别有趣的是，已知环状分子可以有效地封装较小的客体分子，这些相互作用将用于最终的材料和药物递送应用。所描述的项目的技术性质将为不同的本科生和研究生提供聚合物合成和表征方面的特殊跨学科培训经验，以帮助提供训练有素的研究人员来解决未来的材料需求。杜兰大学的研究人员和新奥尔良当地公立学校的贫困学生之间的一个非常成功的以聚合物为主题的推广项目将在该奖项下继续进行，为下一代科学家提供接触现代材料研究的机会，与之互动，并从中获得灵感。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)TECHNICAL SUMMARY: By using a highly efficient reaction to couple a polymer chain?s head and tail, this research project provides a versatile route for preparing cyclic polymers. Because of a variety of synthetic and technical limitations of previous synthetic routes, many fundamental properties of cyclic polymers remain debated, and their potential applications remain under-explored. The developed cyclization approach is powerful in that it can afford high purity cyclic polymers, while also providing access to linear analogs with identical molecular weight distributions. As a result, the effect of the cyclic topology on the polymers physical properties will be probed in a variety of studies, including thermal behavior, rheometry, degradation behavior, small angle x-ray scattering, and antimicrobial activity. In addition, the functional group tolerance of the polymerization and cyclization chemistries enables access to a range of functional cyclic backbones which can be further modified by the attachment of linear or dendritic polymer side-chains. These hybrid structures are of particular interest because the modular synthesis enables control over the size, rigidity, and functionality of the cyclic polymers. Their physical properties and their ability to encapsulate nanomaterials such as buckballs, quantum dots, and single walled nanotubes will be probed as a function of these variables. The overarching goal of this research is to obtain a better fundamental understanding of how the cyclic polymer architecture effects the interactions and physical properties of this family of macromolecules.NONTECHNICAL SUMMARY: Cyclic macromolecules, including plasmid DNA and many biologically relevant peptides, are well known in nature and exhibit unique properties and interactions as a result of their circular topology. However, the ability to efficiently prepare synthetic polymer ?nanoloops? has lagged significantly relative to the advanced synthetic control demonstrate for linear polymers. Using an efficient ?head-to-tail? coupling technique, high purity cyclic polymers can be obtained to probe the fundamental nature and potentially useful properties of these synthetic macromolecules. Of particular interest, cyclic molecules have been known to efficiently encapsulate smaller guest molecules, and these interactions will be explored for eventual materials and drug delivery applications. The technical nature of the described project will provide an exceptional, interdisciplinary training experience in both polymer synthesis and characterization for a diverse set of undergraduate and graduate students to help provide a well-trained body of researchers to address future materials needs. A very successful polymer-themed outreach program between Tulane researchers and predominantly underprivileged students at local New Orleans public schools will be continued under this award, to infuse the next generation of scientists with access to, interaction with, and inspiration from modern materials research.