Mid-Segment Polydispersity as a New Tool for Manipulating ABA Triblock Copolymer Morphologies and Properties

非技术概述具有化学功能和有用物理性质的不寻常组合的创新聚合物材料的开发在其众多应用中至关重要，如高强度结构材料、水和气体净化膜、有机光伏电池组件和高功率锂离子电池材料。在一个高度跨学科的研究环境中，该项目将挑战本科生和研究生在化学，化学工程和材料科学之间的接口进行假设驱动的，横切研究。通过使用合成聚合物化学中的现代方法来生成新材料，并通过表征其结构和伴随的物理性质，该项目旨在发现用于设计具有不寻常形态和各种潜在应用的新特性的创新功能聚合物的新工具。一个本科聚合物化学实验室和两个聚合物为导向的讲座演示将开发用于一般化学教学和在公共宣传lectures.Technical SummaryApplications的商品和特种嵌段共聚物依赖于其有用的组合属性，这源于共价连接两个或更多个不同的均聚物片段成一个单一的大分子。由于嵌段共聚物在化学驱动下自组装成复杂但定义明确的纳米级形态，嵌段共聚物可用作热塑性塑料和热塑性弹性体、先进的分子分离膜和用于制造下一代微电子器件的新模板。现代聚合技术使得能够获得含有化学官能团与有用物理性质的不寻常组合的过多共聚物，代价是将显著的链段分散性引入共聚物的一个或多个嵌段中。然而，宽链段分散性对嵌段共聚物相行为的作用还没有很好地理解。本计画将直接研究中段多分散性对ABA型三嵌段共聚物相行为的影响。模型多分散三嵌段共聚物与不同的链段相互作用参数将合成串联聚合技术的研究其组成相关的相行为，使用小角X-射线散射，电子显微镜，聚合物流变学，和各种运输测量。表征有序-无序转变（ODT）附近的样品将有助于确定这些多组分嵌段共聚物混合物的相行为的参数变量。最终，本研究旨在将链段多分散性转化为一种新的工具，用于操纵嵌段共聚物的形态，具有技术上有用的本体性质。

NON-TECHNICAL SUMMARYThe development of innovative polymeric materials possessing unusual combinations of chemical functionalities and useful physical properties is crucial in their myriad applications as high-strength structural materials, water and gas purification membranes, components in organic photovoltaic cells, and materials for high power lithium-ion batteries. Within a highly interdisciplinary research environment, this project will challenge undergraduate and graduate students to conduct hypothesis-driven, crosscutting research at the interface between chemistry, chemical engineering, and materials science. By using modern methods in synthetic polymer chemistry to generate new materials and by characterizing their structures and attendant physical properties, this project will aim to uncover new tools for designing innovative, functional polymers with unusual morphologies and novel properties for a variety of potential applications. An undergraduate polymer chemistry lab and two polymer-oriented lecture demonstrations will be developed for use in general chemistry instruction and in public outreach lectures.TECHNICAL SUMMARYApplications of commodity and specialty block copolymers rely on their useful combinations of properties, which stem from covalently linking two or more dissimilar homopolymer segments into a single macromolecule. By virtue of their thermodynamically driven self-assembly into complex yet well-defined nanoscale morphologies, block copolymers are useful as thermoplastics and thermoplastic elastomers, advanced molecular separations membranes, and new templates for fabricating next-generation microelectronics. Modern polymerization techniques enable access to a plethora of copolymers containing unusual combinations of chemical functionalities with useful physical properties, at the expense of introducing significant segmental dispersity into one or more blocks of the copolymers. However, the role of broad segmental dispersity on block copolymer phase behavior is not well understood. This project will directly investigate the effects of mid-segment polydispersity on the phase behavior of ABA-type triblock copolymers. Model polydisperse triblock copolymers with varying segmental interaction parameters will be synthesized by tandem polymerization techniques for studies of their composition-dependent phase behavior, using small-angle X-ray scattering, electron microscopy, polymer rheology, and various transport measurements. Characterization of samples near the order-disorder transition (ODT) will help to identify the variables that parameterize the phase behavior of these multicomponent block copolymer mixtures. Ultimately this study aims to transform segmental polydispersity into a new tool for manipulating the morphologies of block copolymers with technologically useful bulk properties.