This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)
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.
