Nanostructured Block Copolymer/Ionic Liquid Composite Materials

技术概述离子液体具有许多吸引人的特性，包括化学和热稳定性、消失的蒸汽压、可调的溶剂化、高离子导电性和高介电常数，这些特性使其成为塑料电子、电池、燃料电池、气体分离膜和致动器的关键成分。为了在应用中实现这些性质，有必要固化材料，和/或将离子液体限制在所需的纳米结构内。嵌段共聚物提供了前所未有的灵活性，可以在1100纳米的长度范围内直接自组装，同时提供机械完整性。将开展五个不同的子项目，总体范围从非常稀薄的溶液到几乎纯的聚合物，旨在从根本上了解如何利用聚合物/离子液体相互作用来制备功能材料。具体地说，这项研究将：(I)扩展胶束穿梭的概念，即共聚物聚集体在水和离子液体之间可逆和完整地转移，以制备在规定温度下加载、转移和释放货物的系统，并制备用于均相催化的纳米乳液；(Ii)通过三嵌段和多嵌段共聚物的自组装制备坚固的离子凝胶，从而在可调温度或光刺激下发生凝胶和熔化；(Iii)优化离子凝胶作为有机晶体管的栅电介质材料的使用，用于塑料电子应用；(Iv)创造机械坚固、有序的嵌段共聚物膜，具有离子液体通道，以实现各向同性和各向异性的高离子传导性和传输；(V)通过离子液体中的氢键，创造具有非常宽范围的驰豫时间可调的超分子聚合物。非技术总结该项目的目标是通过将离子液体与嵌段共聚物相结合来创建一类新的功能纳米结构材料。含有聚合物和离子液体的材料可用于广泛的技术平台，包括塑料电子、致动器、传感器、电池、燃料电池和分离膜。对于应用来说，同时优化几种性能是必不可少的，例如高离子传输、机械完整性和易于加工；这可以通过控制纳米级的材料结构来实现。离子液体已经在欧洲作为化学转化的绿色溶剂投入商业实践；嵌段共聚表面活性剂应该大大扩大可以使用的试剂、产品和催化剂的范围。从事该项目的研究生将接受聚合物合成和高级表征技术方面的广泛培训，并将有机会指导有才华的本科生进行研究。来自大双子城的高中生，特别是女性和代表性不足的少数族裔，将接触到聚合物科学，这是与麻省理工学院教育项目中心举办的“探索职业”夏令营的一部分。来自美国各地高校的教职员工和学生将花时间在PI的实验室里，通过新组建的材料研究设施网络利用一个或多个实验设施。

TECHNICAL SUMMARY Ionic liquids exhibit many appealing properties, including chemical and thermal stability, vanishing vapor pressure, tunable solvation, high ionic conductivity, and high dielectric constant, that render them appealing as key ingredients in plastic electronics, batteries, fuel cells, gas separation membranes, and actuators. To realize these properties in applications, it is necessary to solidify the material, and/or to confine the ionic liquid within a desired nanostructure. Block copolymers offer unprecedented flexibility to direct self-assembly over lengthscales from 1100 nanometers, while simultaneously providing mechanical integrity. Five different sub-projects will be pursued, that collectively range from very dilute solutions to almost pure polymer, and that are aimed at a fundamental understanding of how polymer/ionic liquid interactions can be utilized to prepare functional materials. Specifically, this research will: (i) extend the concept of the micelle shuttle, whereby copolymer aggregates transfer reversibly and intact between aqueous and ionic liquid phases, to prepare systems that load, transfer, and release cargo at prescribed temperatures, and to prepare nanoemulsions for use in homogenous catalysis; (ii) prepare robust ion gels by tri- and multiblock copolymer self-assembly, whereby gelation and melting occur at tunable temperatures or under optical stimulation; (iii) optimize the use of ion gels as gate dielectric materials in organic transistors, for plastic electronic applications; (iv) create mechanically robust, ordered block copolymer membranes with ionic liquid channels for high ionic conductivity and transport, both isotropic and anisotropic; (v) create supramolecular polymers with relaxation times tunable over a remarkably wide range via hydrogen bonding in ionic liquids.NON-TECHNICAL SUMMARYThe goal of this project is to create a new class of functional nanostructured materials by combining ionic liquids with block copolymers. Materials containing polymers and ionic liquids are potentially useful across a wide spectrum of technology platforms, including plastic electronics, actuators, sensors, batteries, fuel cells, and separation membranes. For applications the simultaneous optimization of several properties, such as high ionic transport, mechanical integrity, and facile processing, is essential; this can be achieved through controlling the material structure at the nanoscale. Ionic liquids are already in commercial practice in Europe as green solvents for chemical transformations; block copolymer surfactants should greatly extend the range of reagents, products, and catalysts that can be employed. Graduate students working in this project will be broadly trained in polymer synthesis and advanced characterization techniques, and will have the opportunity to mentor talented undergraduates in research. High school students from the greater Twin Cities, particularly females and underrepresented minorities, will be exposed to polymer science as part of an "Exploring Careers" summer camp administered with the Institute of Technology Center for Educational Programs. Faculty and students from colleges and universities across the US will spend time in the PI's laboratories to utilize one or more of the experimental facilities, through the newly-forged Materials Research Facilities Network.