Ion dynamics and charge transport in ultrathin films of polymerized ionic liquids

非技术综述：现代社会不断增长的能源需求继续为储能设备的广泛研究和开发提供重要推动力。聚合物电解质在这些设备中起着关键作用。该项目将采用专门的电学实验，以更深入地了解极端薄膜中分子的限制以及它们与表面的相互作用对其电气和机械性能的影响。这一基本认识将有助于指导用于可持续技术的具有理想性能的新型功能聚合物电解质的设计，包括用于便携式电池、太阳能电池、燃料电池、致动器、场效应晶体管和电致变色器件的聚合离子液体。所获得的有关聚合物离子液体薄膜的分子结构、聚合物/底物相互作用、离子输运和动力学之间的相互作用的信息，不仅对离子液体领域，而且对聚合物科学和工程科学界都是有益的。该项目的一个重要组成部分还涉及几项综合教育活动。该项目将通过研究生和本科生积极参与这项研究，促进聚合物纳米技术和材料科学专家的培训和教育。技术概要：聚合离子液体是一种新型的功能聚合物，它结合了分子离子液体独特的物理化学性质(如宽的电化学窗口、可忽略的蒸汽压和离子导电性)和聚合物的突出机械特性。这些材料具有广泛的应用前景，包括染料敏化太阳能电池、便携式电池、致动器、场效应管和电致变色器件。其中许多技术涉及将聚合离子液体限制在一维空间中作为薄膜使用。然而，对一维纳米尺度限制对聚合离子液体中离子输运和动力学的影响的基本了解仍然非常有限。本研究的主要目的是揭示聚合物离子液体超薄膜中电荷输运和离子动力学的控制机制。该项目将集中于：(I)研究膜厚对聚合离子液体中离子传导和动力学的影响，(Ii)揭示聚合物/基质相互作用对离子输运和动力学的作用，以及(Iii)研究化学成分/结构对聚合离子液体薄膜中离子动力学和电荷输运的影响。这项研究将主要利用最近开发的具有二氧化硅纳米结构和气隙的电极配置对聚合物薄膜进行宽带介电光谱测量。这些研究对一维受限对离子输运和动力学的影响有了详细的基础了解，这将为设计更有效的适合于电化学电源和器件的聚合物电解质提供坚实的科学基础。

NON-TECHNICAL SUMMARY:The rising energy needs of the modern society continue to provide a significant impetus for extensive research and development in energy storage devices. Polymer electrolytes play a key role in these devices. This project will employ specialized electrical experiments to gain deeper understanding of the impact of the confinement of the molecules within extrememly thin films and their interactions with surfaces on their electrical and mechanical properties. This fundamental understanding will be useful in guiding the design of novel functional polymer electrolytes with desirable properties for sustainable technologies, including polymerized ionic liquids for portable batteries, solar cells, fuel cells, actuators, field-effect transistors, and electrochromic devices. The information regarding the interplay between molecular structure, polymer/substrate interactions, ion transport and dynamics in thin films of polymerized ionic liquids gained from this work will be beneficial not only within the field of ionic liquids but also to the polymer science and engineering scientific 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. This integrated research/educational program also emphasizes work with underrepresented groups and outreach to K-12 students.TECHNICAL SUMMARY:Polymerized ionic liquids are a novel class of functional polymers that combine the unique physicochemical properties of molecular ionic liquids (e.g. wide electrochemical windows, negligible vapor pressures, and ionic conduction) with the outstanding mechanical characteristics of polymers. These materials are promising for a variety of applications including dye-sensitized solar cells, portable batteries, actuators, field-effect transistors and electrochromic devices. Many of these technologies involve the use of polymerized ionic liquids confined in one dimension as thin films. However, fundamental understanding of the impact of one-dimensional nanoscale confinement on ion transport and dynamics in polymerized ionic liquids is still very limited. The main goal of this research is to unravel the mechanisms controlling charge transport and ion dynamics in ultrathin films of polymerized ionic liquids. The project will focus on: (i) investigating the impact of film thickness on ion conduction and dynamics in polymerized ionic liquids, (ii) unraveling the role of the polymer/substrate interactions on ion transport and dynamics, and (iii) investigating the role of chemical composition/structure on ion dynamics and charge transport in thin films of polymerized ionic liquids. The research will primarialy utilize broadband dielectric spectroscopy measurements of thin polymer films using a recently developed electrode configuration featuring silica nanostructures and an air gap. The detailed fundamental understanding of the impact of one-dimensional confinement on ion transport and dynamics gained in these studies will provide a firm scientific basis for design of more efficient polymer electrolytes suitable for potential use in electrochemical power sources and devices.