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》(Public Law 111-5)获得资助的。技术概述：通过使用高效的反应来偶联聚合物链--S的头部和尾部，该研究项目为制备环状聚合物提供了一种多样化的方法。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然存在争议，它们的潜在应用仍然没有得到充分的探索。开发的环化方法是强大的，因为它可以提供高纯度的环状聚合物，同时也提供了获得具有相同分子量分布的线性类似物的途径。因此，环状拓扑结构对聚合物物理性能的影响将在各种研究中得到探索，包括热行为、流变学、降解行为、小角X射线散射和抗菌活性。此外，聚合和环化化学试剂的官能团耐受性使得能够获得一系列功能环状主链，这些主链可以通过连接线状或树枝状聚合物侧链来进一步修饰。这些杂化结构特别令人感兴趣，因为模块化合成能够控制环状聚合物的大小、刚性和功能。它们的物理性质以及它们包裹纳米材料(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讨。这项研究的主要目标是更好地从根本上了解环状聚合物的结构如何影响这类大分子的相互作用和物理性质。非技术摘要：环状大分子，包括质粒DNA和许多生物相关的多肽，在自然界中是众所周知的，由于它们的环状拓扑结构，表现出独特的性质和相互作用。然而，高效制备合成聚合物的能力？纳米环？与线性聚合物的先进合成控制演示相比，已经明显落后。使用一种高效的？从头到尾？通过偶联技术，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。尤其令人感兴趣的是，已知环状分子能够有效地包裹较小的客体分子，这些相互作用将被探索用于最终的材料和药物输送应用。所述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，以帮助提供一支训练有素的研究人员队伍，以满足未来的材料需求。杜兰大学研究人员和当地新奥尔良公立学校的贫困学生之间非常成功的聚合物主题外展项目将在该奖项下继续下去，向下一代科学家灌输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.