Theory of Polymer Crystallization

该奖项支持理论研究和教育，旨在通过采用模拟技术和统计力学开发聚合物结晶和定向聚合物组装的理论。聚合物溶液和熔体的结晶是高分子科学中一个长期的研究领域。对聚合物链如何组织成分级结构的基本理解仍然是难以捉摸的。柔性高分子的构象熵使高分子的结晶现象有别于小分子体系的有序化。聚合物的相同熵方面在二嵌段共聚物和生物聚合物的各种定向组装体中表现出来。PI以前的工作，以解决构象熵的影响，导致了解释聚合物结晶的丰富现象的新方法。这些都是补充传统的论点在文献中，基本上忽略了构象熵。该奖项支持的研究将建立在最近的新想法，探索聚合物的几个相关的有序现象。 具体而言，（a）聚合物球晶中的层状形态，（B）聚合物溶液和熔体中生长前沿的动力学，以及（c）聚合物的定向组装将得到解决。该项目旨在建立新的概念模型和发现聚合物组装的新规律。非技术总结该奖项支持综合计算和理论研究以及教育，旨在了解聚合物（由许多较小的重复分子单元组成的大型长链分子）如何组织成有序状态。特别令人感兴趣的是它们是如何结晶的。长链分子可以以多种方式扭曲和弯曲，这使得聚合物的结晶过程与许多其他材料的结晶过程不同。PI将使用计算机模拟，并建立在以前的工作，他自己的和其他人的，以发展对聚合物结晶的理解。这项研究的结果可能会在许多应用领域产生影响，例如聚合物加工，聚合物材料的制造规模比人类头发小一万倍，以及分子和其他材料的“构建块”组装形成生物结构和生命物质的过程。 许多（如果不是大多数）现代材料是由加工的半结晶聚合物制成的，这是所提出的理论和建模研究的主题。对这类重要材料的行为的基本理解将有助于设计和加工新型聚合物材料，从而为我们的社会带来更大的利益。这项活动为培养这一具有挑战性的研究领域的研究生和21世纪的劳动力提供了支持。

TECHNICAL SUMMARYThis award supports theoretical research and education with an aim to develop theories of polymer crystallization and directed polymer assembly, by employing simulation techniques and statistical mechanics. Crystallization of polymers from solutions and melts is one of the longstanding research areas in polymer science. A fundamental understanding of how polymer chains organize into hierarchical structures remains elusive. The conformational entropy of flexible polymer molecules makes the crystallization phenomenon of polymers distinct from ordering of small molecular systems. The same entropic aspects of polymers are manifest in various directed assemblies of diblock copolymers and biological polymers. Previous work by the PI to address the effects of the conformational entropy has resulted in novel ways of interpreting the rich phenomenology of polymer crystallization. These are complementary to the traditional arguments in the literature, which essentially ignore the conformational entropy. This award supports research that will build on recent new ideas to explore several related ordering phenomena of polymers. Specifically, (a) lamellar morphology in polymeric spherulites, (b) kinetics of growth fronts in polymer solutions and melts, and (c) directed assembly of polymers will be addressed. This project is aimed at building new conceptual models and discovering new laws of polymer assembly. The proposed theoretical work complements experimental investigations being actively pursued in laboratories worldwide.NON-TECHNICAL SUMMARYThis award supports integrated computational and theoretical research and education aimed to understand how, polymers, large long-chain molecules made of many smaller repeating molecular units, organize into ordered states. Of particular interest is how they crystallize. The many ways long-chain molecules can twist and bend makes the crystallization process of polymers distinct from that of many other materials. The PI will use computer simulations and build on previous work, his own and that of others, to develop an understanding of polymer crystallization. The results of this research may have impact in numerous applied areas such as polymer processing, the fabrication of polymeric materials down to scales some ten thousand times smaller than a human hair, and the process by which molecules and other 'building blocks' of materials assemble themselves to form biological structures and living matter. Many, if not most, modern materials are made from processed semicrystalline polymers, which are the subjects of the proposed theoretical and modeling investigation. A fundamental understanding of the behavior of this important class of materials will help to design and process novel polymeric materials with enhanced benefits to our society. This activity provides support for training of graduate students in this challenging research area and the workforce of the twenty first century.