Design, Structure, and Properties of Polymeric Materials with Programmed Macromolecular Architectures

第一部分：非技术总结本研究计划将从金属合金相冶金学的基本原理和生物学的一些最基本的原理（如同手性）的组合中汲取灵感，并将其应用于具有简单和复杂结构的单个大分子的设计和合成，这些结构可能包括记忆效应，这将允许在复杂的聚合物材料中发现新概念。预计这些概念将与目前生物学中最有效的方法竞争。这项工作的结果预计将有助于控制超分子电子特性的应用，如太阳能电池，医疗设备的新工具，包括药物输送，聚合物材料的环境方面，和其他用途。这项研究涉及有机，大分子和超分子化学，物理学，生物学，合成生物学和材料科学之间的跨学科计划;它还包括与来自世界各地的科学家合作。该计划还将使本科生和研究生，高中生和博士后科学家的教育。第2部分：技术总结弗兰克-卡斯珀相首次发现和金属合金中使用。在软物质中，它们在相关的NSF计划中被发现，最近也在嵌段共聚物，表面活性剂和其他组件中被发现。预计它们将很快发展成为新的技术应用。然而，许多超分子球形组装体是螺旋形的，因此手性和分子机制以及同手性在这些相中的作用仍有待了解。 在这些材料中的记忆效应所产生的结构和性能，只有通过手性超分子树枝状聚合物和其他单分散组装体才能获得。因此，本项目将阐明手性在Frank-Kasper软相中的作用，并将为从聚合物和任何其他有机材料开发新材料性能奠定基础。尽管大多数聚合物和有机材料表现出螺旋结构，因此是手性的，但当它们由非手性或外消旋构建块组装时，它们被认为是外消旋的，并显示出低有序的结构和性能。 这种超分子趋势类似于全同立构（纯手性）、间同立构（杂手性）和无规立构（外消旋）聚合物。 最近发现了一种新的结晶机制，即不考虑手性的齿轮机制，并显示出潜在地能够消除关于由手性与外消旋结构单元产生的螺旋结构的完美性的差异。将研究这种机制的一般性，以产生相同的材料性能的纯手性的外消旋和非手性积木的组合。这项研究的成果将对许多类型的材料产生广泛的科学影响，包括电子，医疗和其他应用。该项目的另一个方面涉及单分散聚合物。 含有单维物种的单分散聚合物仅由生物产生。这项研究将包括自中断活性聚合的持续发展，这将使真正的单分散聚合物与标准活性聚合产生的窄分散性聚合物的结构和性能之间的相似性和差异的研究成为可能。 这一奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

PART 1: NON-TECHNICAL SUMMARYThis research program will draw inspiration from a combination of fundamental principles derived from the metallurgy of metal alloy phases and some of the most fundamental principles of biology such as homochirality, and apply them to the design and synthesis of individual macromolecules with simple and complex architectures that may include memory effects, which will allow to discover new concepts in complex polymeric materials. These concepts are anticipated to be competitive with the most efficient methodologies currently available in biology. The outcome of this work is expected to facilitate control of supramolecular electronic properties of interest for applications such as solar cells, new tools for medical devices including drug delivery, environmental aspects of polymer materials, and other uses. This research involves an interdisciplinary program at the interface between organic, macromolecular and supramolecular chemistry, physics, biology, synthetic biology, and materials science; it also includes collaborations with scientists from around the world. This program will also enable the education of undergraduate and graduate students, high-school students, and postdoctoral scientists.PART 2: TECHNICAL SUMMARYThe Frank-Kasper phases were first discovered and employed in metal alloys. In soft matter they were discovered in a related NSF program and recently also in block-copolymers, surfactants and other assemblies. They are expected to evolve soon into new technological applications. However, many supramolecular spherical assemblies are helical and therefore chiral and the molecular mechanism as well as the role of homochirality in these phases remains to be understood. The structures and properties generated by memory effects in these materials are accessible only by chiral supramolecular dendrimers and by other monodisperse assemblies. Therefore, this project will elucidate the role of chirality in Frank-Kasper soft phases and will be fundamental for the development of new material properties from polymers and any other organic materials.Even though most polymeric and organic materials exhibit helical structures and are therefore chiral, they are considered to be racemic when assembled from achiral or racemic building blocks and display low-ordered structures and properties. This supramolecular trend is similar to that of isotactic (homochiral), syndiotactic (heterochiral), and atactic (racemic) polymers. A new mechanism of crystallization, the cogwheel mechanism that disregards chirality, has recently been discovered and shown to be potentially able to eliminate the difference regarding the perfection of helical structures generated from chiral versus racemic building blocks. The generality of this mechanism to combinations of racemic and achiral building blocks to generate the same material properties as the homochiral ones will be studied. The outcome of this research will have broad scientific impact across many types of materials, including electronic, medical, and other applications.Another aspect of this project involves monodisperse polymers. Monodisperse polymers containing single-dimension species are produced only by biology. This research will include continued development of self-interrupted living polymerization, which will enable study of similarities and differences between the structure and properties of truly monodisperse polymers versus those of narrow dispersity produced by standard living polymerizations. These will also impact broad areas involving the design of polymeric materials with numerous potential applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.