Entangled Polymers by Design Using Supramolecular Chemistry

在这个由化学系大分子、超分子和纳米化学项目资助的项目中，弗吉尼亚理工学院和州立大学的Harry吉布森将合成和研究大分子，其中分支点、交联或重复单元是轮烷或索烃形式的机械连接。 各种聚合技术（e.例如，在一个实施例中，阴离子、原子转移自由基、氮氧介导的、经典自由基和开环复分解）将用于制备具有末端、中心或多个主体和客体官能团的明确定义的大分子。然后这些聚合物将自组装成各种拓扑结构（星星、H-支化、聚[2]轮烷、瓶刷等）。均聚物和共聚物形式，都涉及轮烷键，一些拓扑结构不容易以其他方式获得。 由于轮烷单元中存在的环状和线性组分之间的恢复力，这些超分子轮烷聚合物预期相对于共价聚合物表现出增强的性质。 形态学，流变学，热和机械研究将阐明这些系统的新特性和反应，将它们与正常的共价连接的大分子区分开来，为通过超分子科学实现的最终特性提供新的见解。更广泛的影响包括培养本科生和研究生以及博士后研究人员，持续致力于培养来自化学科学领域代表性不足的群体的学生，并通过在期刊上发表文章和在会议上发表演讲来传播研究成果。这项工作将增强我们对通过互锁环和链机械连接的聚合物及其物理行为的基本理解。 聚合物链是许多塑料材料的基本单元，新型聚合物的开发可能会导致生物医学材料，涂料和复合材料的新应用。

In this project funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Harry Gibson of the Virginia Polytechnic Institute and State University will synthesize and study macromolecules in which branch points, crosslinks or repeat units are mechanical connections in the form of rotaxanes or catenanes. A variety of polymerization techniques (e. g., anionic, atom transfer radical, nitroxide mediated, classical free radical and ring opening metathesis) will be employed to prepare well-defined macromolecules with terminal, central or multiple host and guest functionalities. These polymers will then be self-assembled into a variety of topologies (star, H-branched, poly[2]rotaxane, bottle brush, etc.) in both homopolymeric and copolymeric forms, all involving rotaxane linkages, some topologies not readily accessible otherwise. These supramolecular rotaxane polymers are expected to exhibit enhanced properties relative to covalent polymers because of the restoring force between the cyclic and linear components present in the rotaxane units. Morphological, rheological, thermal and mechanical studies will elucidate the novel properties and responses of these systems that distinguish them from normal covalently linked macromolecules, providing new insights into the ultimate properties that are achievable through supramolecular science. The broader impacts involve training undergraduate and graduate students as well as postdoctoral researchers, an ongoing commitment to training students from groups underrepresented in the chemical sciences, and disseminating research results through publications in journals and presentations at conferences.This work will enhance our fundamental understanding about polymers linked mechanically via interlocking loops and chains and their physical behavior. Polymer chains are the fundamental units of many plastic materials, and the development of new types of polymers could lead to new applications in biomedical materials, coatings, and composites.