Supramolecularly Templated Living REP-ROP Polymerizations and Block Copolymers

凯尔特人的艺术、童子军结、莫比乌斯带环和M.C.埃舍尔的艺术让观众着迷，也挑战了他们追踪连接起源的能力。一段时间以来，数学家们一直将环的拓扑和循环重叠结构的可编程性质描述为所谓的纽结理论。在聚合物科学中，了解聚合物链变得多长以及如何使这些缠结的链在溶液中溶解，可以产生具有有趣的物理和化学特性的新材料，这些材料可以扩展塑料、涂料、橡胶和复合材料的应用。在这个跨学科和实用的领域，有很多机会来培训和指导未来的科学家。这项研究有助于培养一支能够解决复杂问题并生产有价值产品的劳动力。本项目致力于通过单体开环(RO)和大分子引发剂扩环聚合(REP)或REP-ROP聚合来设计和合成新型链状聚合物和嵌段共聚物组合物。利用纽结理论，有可能获得各种可控缠结的打结大分子，以及高产率和高相对分子质量的嵌段共聚物组成。合成链状大分子的方法包括：1)基于邻菲咯啉的大分子引发剂模板；2)基于原子转移自由基聚合方法的均聚物和嵌段共聚物；3)聚己内酯的扩环策略；4)改变侧基和控制链的组成和相互作用参数的聚合物反应。表征方法包括核磁共振光谱、MALDI质谱学、原子力显微镜、尺寸排除层析和流变学，它们验证了聚合物在溶液和固态中的化学结构、拓扑结构和相分离。寻求与聚合物物理学家、理论家和流变学家的合作，以利用链状聚合物的性质作为材料和相容剂用于实际应用。

Celtic art, Boy Scout knots, Mobius strip rings, and M.C. Escher's art have fascinated the viewer and challenged their ability to trace the origin of connectivity. For some time now, mathematicians have described the topology of rings and cyclic overlapping structures with their programmable qualities into the so-called Knot Theory. In polymer science, understanding how long polymer chains become tangled and how to get those tangled chains to dissolve in a solution can result in new materials with interesting physical properties and chemical properties that can extend the applications of plastics, coatings, rubber, and composites. There are many opportunities for training and mentoring future scientists in this interdisciplinary and practical field. This research helps preparing a workforce that solves complex problems and produces valuable products. This project focuses on the design and synthesis of new catenated polymer and block copolymer compositions via monomer ring opening (RO) and macroinitiator ring expansion polymerizations (REP) or REP-ROP Polymerizations. By utilizing the Knot Theory, it may be possible to obtain various knotted macromolecules, which have controlled entanglements as well as block copolymer composition with high yields and high molecular weight. The approaches towards the synthesis of catenated macromolecules involve: 1) phenanthroline-based macroinitiator templates; 2) homopolymers and block copolymers derived from atom transfer radical polymerization methods and ring closures with atom transfer radical coupling; 3) ring expansion strategies with polycaprolactones; and 4) polymer reactions that modify the side groups and control the composition and interaction parameters of the chains. Characterization methods include nuclear magnetic resonance spectroscopy, MALDI mass sppectrometry, atomic force microscopy, size-exclusion chromatography, and rheometry, which verify the polymer's chemical structure, topology, and phase separation in solution and solid state. Collaborations with polymer physicists, theorists, and rheologists are pursued to harness the properties of the catenated polymers as materials and compatibilizers for practical applications.