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

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动力。聚合物电解质在这些器件中起着关键作用。该项目将采用专门的电学实验，以更深入地了解分子在极薄薄膜中的限制及其与表面的相互作用对其电学和机械性能的影响。这种基本的理解将是有用的，在指导新的功能性聚合物电解质的设计与可持续发展的技术，包括聚合离子液体的便携式电池，太阳能电池，燃料电池，致动器，场效应晶体管，和电致变色器件所需的性能。从这项工作中获得的关于聚合离子液体薄膜中分子结构，聚合物/基底相互作用，离子传输和动力学之间的相互作用的信息不仅在离子液体领域内，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。技术概述：聚合离子液体是一类新型的功能高分子，它将分子离子液体独特的物理化学性质（如宽的电化学窗口、可忽略的蒸气压和离子导电性）与聚合物突出的机械特性结合在一起，具有联合收割机的特点。这些材料在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等方面有着广泛的应用前景。这些技术中的许多涉及使用聚合的离子液体作为薄膜限制在一维中。然而，在聚合离子液体中的离子传输和动力学的一维纳米限制的影响的基本理解仍然是非常有限的。本研究的主要目的是揭示聚合离子液体膜中电荷传输和离子动力学的控制机制。该项目将侧重于：（i）研究膜厚度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/基底相互作用对离子传输和动力学的作用，和（iii）研究聚合离子液体薄膜中化学组成/结构对离子动力学和电荷传输的作用。这项研究将主要利用宽带介电谱测量薄聚合物薄膜使用最近开发的电极配置具有二氧化硅纳米结构和空气间隙。在这些研究中获得的一维约束对离子输运和动力学的影响的详细基本理解将为设计更有效的聚合物电解质提供坚实的科学基础，适合于在电化学电源和设备中的潜在用途。

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.