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

非技术总结创新聚合物材料具有独特的化学功能和有用的物理性能组合，在其作为高强度结构材料、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的众多应用中至关重要。在一个高度跨学科的研究环境中，这个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进行假设驱动的交叉研究。通过使用合成聚合物化学中的现代方法来产生新材料，并通过表征其结构和随之而来的物理性能，该项目旨在发现新的工具，以设计具有独特形态和新颖性能的创新功能聚合物，用于各种潜在的应用。将开发一个本科生聚合物化学实验室和两个面向聚合物的讲座演示，用于一般化学教学和公共推广讲座。技术总结商品和特种嵌段共聚物的应用依赖于它们有用的性能组合，这些组合源于将两个或多个不同的均聚物链段共价连接到一个大分子中。由于其热力学驱动自组装成复杂但定义良好的纳米级形态，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制造下一代微电子的新模板。现代聚合技术能够获得大量的共聚物，这些共聚物包含具有有用物理性质的化学官能团的不寻常组合，但代价是将显著的链段分散性引入到一个或多个共聚物嵌段中。然而，广泛的链段分散性对嵌段共聚物相行为的作用还不是很清楚。本项目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。通过串联聚合技术合成具有不同链段相互作用参数的模型多分散三嵌段共聚物，利用小角X射线散射、电子显微镜、聚合物流变学和各种输运测量来研究其组成相关的相行为。对有序-无序转变(ODT)附近样品的表征将有助于识别描述这些多组分嵌段共聚物混合物相行为的变量。最终，本研究旨在将嵌段多分散性转变为一种新的工具，用于操纵具有技术上有用的本体性质的嵌段共聚物的形态。

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.