From Micelles to Membranes: Advanced Block Polymer Ionic Liquid Composites

从胶束到膜：先进嵌段聚合物离子液体复合材料

• 批准号: 1206459
• 负责人: Timothy Lodge
• 金额: $ 45万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-05-01 至 2017-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1206459&HistoricalAwards=false
• 关键词: Micelles; Membranes; Advanced; Block; Polymer

TECHNICAL SUMMARY:The goal of this project is to advance a new class of functional nanostructured materials by combining ionic liquids with block copolymers. 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 potential 'green' solvents, and as key ingredients in plastic electronics, batteries, fuel cells, gas separation membranes, and actuators. To realize these properties in advanced materials 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 1-100 nanometers, while simultaneously providing mechanical integrity. Three different sub-projects are envisioned that address fundamental issues in polymer materials science, and each exploits a unique aspect of nanostructured copolymer/ionic liquid mixtures. First, a quantitative understanding of the rate of chain exchange in block copolymer micelles will be established, by utilizing time-resolved small-angle neutron scattering on isotopically labeled micelle mixtures. By virtue of the wide usable temperature range of ionic liquids, and the ease with which critical micellization temperatures can be tuned predictably by blending homologous imidazolium cations, the crossover from 'ergodicity' to 'non-ergodicity' will be delineated systematically. Second, the recent discovery of ionic-liquid-filled vesicles dispersed in water will be extended to nanoreactor applications, whereby the catalyst is confined to the vesicle interior, and may be recovered easily. The aqueous matrix mitigates the severe cost and mass transfer restrictions of ionic liquid reaction media, while the vesicle membrane will regulate the rate of reactant and product partitioning between aqueous and ionic liquid phases. Last, an ABC triblock terpolymer approach is proposed to prepare crosslinked bi- and tri-continuous membranes with conductive, ionic-liquid-rich nanochannels, with the goal of accessing unprecedented combinations of high mechanical toughness and ionic conductivity.NON-TECHNICAL SUMMARY:Composite materials prepared from polymers and room temperature ionic liquids are under active consideration for many advanced technologies, including biomass modification, gas separation membranes, plastic electronics, ion batteries, and fuel cells. Success in any of these areas would have profound societal impact in terms of energy conservation, sustainable plastics, and portable energy storage. Simultaneous optimization of diverse properties, such as high ionic transport, mechanical integrity, and facile processing, can best be achieved through structural control at the nanometer scale. Thus, the combination of structure-directing block copolymers and functional ionic liquids will accelerate the development of advanced materials. Graduate students will acquire a broad suite of skills in polymer synthesis and characterization, light, x-ray and neutron scattering, fluorescence spectroscopy, and electron microscopy. They will also have extensive opportunities to present technical talks and posters to external audiences, as well as to mentor talented undergraduates in research. High school students from the greater Twin Cities, particularly women and underrepresented minorities, will be exposed to polymer science through "Polymer Day: You Make It, You Break It", a hands-on component of a broader "Exploring Careers in Science & Engineering" summer camp.

技术概述：该项目的目标是通过结合离子液体和嵌段共聚物来推进一类新的功能纳米结构材料。离子液体表现出许多吸引人的特性，包括化学和热稳定性、蒸气压消失、可调节的溶剂化、高离子电导率和高介电常数，使它们成为潜在的“绿色”溶剂，以及塑料电子、电池、燃料电池、气体分离膜和执行器的关键成分。为了在先进材料应用中实现这些特性，有必要固化材料，和/或将离子液体限制在所需的纳米结构中。嵌段共聚物提供了前所未有的灵活性，可以在1-100纳米的长度范围内直接进行自组装，同时提供了机械完整性。预计将有三个不同的子项目解决高分子材料科学的基本问题，每个子项目都利用纳米结构共聚物/离子液体混合物的独特方面。首先，通过对同位素标记胶束混合物利用时间分辨小角中子散射，将建立对嵌段共聚物胶束中链交换速率的定量理解。由于离子液体的可用温度范围很广，并且可以通过混合同源咪唑阳离子来预测地调节临界胶束温度，因此将系统地描述从“遍历性”到“非遍历性”的交叉。其次，最近发现的分散在水中的充满离子液体的囊泡将扩展到纳米反应器的应用，其中催化剂被限制在囊泡内部，并且可能很容易回收。水性基质减轻了离子液体反应介质的成本和传质限制，而囊泡膜将调节水相和离子液相之间的反应物和产物分配速率。最后，提出了一种ABC三嵌段三元共聚物方法来制备具有导电、富含离子液体的纳米通道的交联双连续和三连续膜，其目标是获得前所未有的高机械韧性和离子电导率的组合。非技术概要：由聚合物和室温离子液体制备的复合材料正被积极考虑用于许多先进技术，包括生物质改性、气体分离膜、塑料电子、离子电池和燃料电池。在这些领域中的任何一个领域取得成功都将在节能、可持续塑料和便携式能源储存方面产生深远的社会影响。同时优化多种性能，如高离子输运、机械完整性和易于加工，可以通过纳米尺度的结构控制来实现。因此，定向结构嵌段共聚物与功能离子液体的结合将加速先进材料的发展。研究生将获得聚合物合成和表征，光，x射线和中子散射，荧光光谱和电子显微镜方面的广泛技能。他们还将有广泛的机会向外部观众发表技术演讲和海报，以及指导有才华的本科生进行研究。来自双子城的高中生，尤其是女性和少数族裔，将通过“聚合物日：你创造它，你打破它”来接触聚合物科学，这是一个更广泛的“探索科学与工程职业”夏令营的实践组成部分。