CAS-Climate: Ion and Interfacial Dynamics in Polymerized Ionic Liquids

非技术总结：如果不开发新型、高性能、清洁的能源转换和存储设备，我们社会不断增长的能源需求就无法得到满足。电解质是这些装置的关键组成部分，因为这些材料是选择性传输目标电活性物质的介质。然而，安全性、稳定性和选择性问题是许多先进电解质持续关注的问题。当前项目的一个独特焦点是研究利用约束和界面相互作用来增强聚合离子液体中电荷传输的新方法，这将使它们适合作为电解质。从计划研究中获得的基本理解将为许多与可持续性相关的技术应用提供深思熟虑和优化聚合物设计的基础，例如电池，燃料电池和超级电容器，其中界面在决定整体功能方面起着重要作用。此外，从该项目中获得的关于与聚合物接触的固体表面的化学影响、聚合物的类型、限制程度和样品制备条件的知识将有益于聚合物科学和工程界。这个项目的一个重要组成部分还包括若干综合教育活动。该项目将通过研究生和本科生积极参与这项研究，为聚合物纳米技术和材料科学专家的培训和教育做出贡献。该计划强调与代表性不足的群体合作，并为高中生提供研究经验。技术概述：聚合离子液体是一类新型功能聚合物电解质，它结合了分子离子液体独特的物理化学特性（如：不可燃性、宽电化学窗口、可忽略的蒸气压和离子导电性）和聚合物的杰出机械特性。这些材料有望用于各种清洁能源应用，包括染料敏化太阳能电池、便携式电池、致动器、场效应晶体管和电致变色器件。然而，它们的离子电导率，这是电化学能量应用背景下最关键的性质之一，与聚合时的低分子量对偶物相比，下降了许多数量级。在该项目中，将研究一种新的方法，以发展对具有高离子电导率和其他理想电化学性能的聚合离子液体的合理设计的基本理解。计划研究的总体目标是利用纳米尺度的约束和界面力来开发一个基本框架，用于设计具有增强离子导电性的聚合离子液体。计划工作的主要目标是：(1)对纳米级限制程度（通过平均孔径和聚合物薄膜厚度反映）对聚合动力学、离子传输和受限聚合离子液体动力学的影响有一个基本的理解；(2)揭示聚合物/孔壁相互作用在聚合动力学、离子动力学和电荷传输中的作用；(3)研究聚合离子液体的分子结构（化学）对其离子动力学和电荷在纳米孔中的输运的影响；(4)阐明约束维度（类型）对聚合动力学、离子输运和受限聚合离子液体动力学的影响。从该项目中获得的对纳米尺度限制影响的详细基本理解将为设计具有可持续性和众多技术独特性能的功能聚合物提供科学框架。该奖项反映了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，认为值得支持。

NON-TECHNICAL SUMMARY:The rising energy needs of our society cannot be met without development of novel, high-performance, clean-energy conversion and storage devices. Electrolytes are a critical component of these devices, as these materials are the media for selective transport of the target electroactive species. However, safety, stability, and selectivity issues are an on-going concern in many state-of-the-art electrolytes. A unique focus of the current project is the investigation of novel approaches to enhance charge transport in polymerized ionic liquids by taking advantage of confinement and interfacial interactions, which would make them suitable as electrolytes. The fundamental understanding obtained from the planned research will provide a basis for deliberate and optimal design of polymers for many sustainability-relevant technological applications, such as batteries, fuel cells, and supercapacitors, where interfaces play a significant role in determining the overall functionality. In addition, the knowledge gained from this project concerning the impact of the chemistry of solid surfaces in contact with polymers, the type of polymer, extent of confinement and sample preparative conditions will be of benefit to the polymer science and engineering communities. An important component of this project also involves several integrated educational activities. The project will contribute to training and education of specialists in polymer nanotechnology and materials science through active involvement of graduate and undergraduate students in this research. The proposed program emphasizes work with underrepresented groups and research experiences for high school students.TECHNICAL SUMMARY:Polymerized ionic liquids are a class of novel functional polymer electrolytes that combines the unique physicochemical properties of molecular ionic liquids (e.g. non-flammability, wide electrochemical windows, negligible vapor pressures, and ionic conduction) with the outstanding mechanical characteristics of polymers. These materials are promising for a variety of clean-energy applications including dye-sensitized solar cells, portable batteries, actuators, field-effect transistors and electrochromic devices. However, their ionic conductivity, which is one of the most critical properties in the context of electrochemical energy applications, drops by many orders of magnitude in comparison to their low molecular weight counterparts upon polymerization. In the proposed project, a new approach to developing fundamental understanding for rational design of polymerized ionic liquids with high ionic conductivity and other desirable electrochemical properties will be investigated. The overall goal of the planned research is to employ nanoscale confinement and interfacial forces to develop a fundamental framework for designing polymerized ionic liquids with enhanced ionic conduction. The major objectives of the planned work are to: (i) develop a fundamental understanding of the impact of the extent of nanoscale confinement (as reflected by the mean pore diameters and polymer film thicknesses) on polymerization kinetics, ion transport and dynamics in confined polymerized ionic liquids, (ii) unravel the role of polymer/pore-wall interactions on polymerization kinetics, ion dynamics and charge transport, (iii) investigate the effect of molecular structure (chemistry) of polymerized ionic liquids on their ion dynamics and charge transport in nanopores, and (iv) elucidate the impact of the dimensionality (type) of confinement on polymerization kinetics, ion transport and dynamics in confined polymerized ionic liquids. The detailed fundamental understanding of the impact of nanoscale confinement gained from this project will provide a scientific framework for the design of functional polymers with relevance to sustainability and unique properties for numerous technologies, including polymer electrolytes suitable for use in electrochemical power sources and devices..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.