Self assembly, dynamics and charge transport in bulk ionic liquids and ionogels

本体离子液体和离子凝胶中的自组装、动力学和电荷传输

• 批准号: 417469938
• 负责人: Professor Dr. Thomas Blochowicz
• 金额: --
• 依托单位: School of Physics & Astronomy
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/417469938?language=en
• 关键词: Self; assembly; dynamics; charge; transport

Ionic Liquids (ILs), i.e. molten salts that are liquid at room temperature, are liquids with unusual properties that have many potential applications, e.g. in what is known as "green chemistry" or in energy applications. Many ionic liquids, due to their amphiphilic molecular architecture, tend to show self-assembly and structure formation on the mesoscale (i.e. formation of polar and apolar domains), which influences molecular dynamics and ion transport in these materials. It is the aim of the current project to understand, how charge transport and molecular dynamics depend on the ionic liquid mesostructure, with particular emphasis on coupling/decoupling phenomena of charge transport and structural relaxation in these systems.Therefore in this project a series of Ils with varying tendency to form polar/apolar domains is investigated (realized, e.g. by varying the alkyl chain length of a cation or by addition of small amounts of solvents) with respect to molecular dynamics and ion transport. In the next step it is planned to investigate Ils in ionogels. The latter systems are based on ionic liquids by adding various network forming agents. In these materials high conductivity is often combined with almost solid-like mechanical properties, which makes them particularly interesting for many applications. In the ionogels the effect of inner surfaces on the IL structure formation and on dynamics and charge transport are to be clarified. In particular, interesing effects are expected when the length scale of geometric confnement by the network forming agent meets the lengthscale of domains and aggregates in the IL. In terms of experimental method, the emphasis in the current project is on depolarized dynamic light scattering, which unambiguously identifies molecular reorientation and is not influenced by charge transport or polarization effects. A combination of different light scattering techniques (photon correlation, Tandem Fabry Perot and Raman spectroscopy) allows us to cover the full relevant spectral range, between 1 mHz up to about 10 THz. At the same time broadband dielectric spectroscopy (between 1 Microherz and 50 GHz) will provide information on the charge transport in the system. In that way it will be possible to unambiguously separate molecular dynamics and charge transport. The temperature dependent domain structure in the ILs will be monitored by small angle scattering techniques. Therefore, we expect to improve our understanding of the interrelation of structure formation, dynamics and charge transport in ILs and in ionogels, which, on the long run, will help to realize knowledge-based material design with ionic liquids.

离子液体（IL），即在室温下为液体的熔融盐，是具有不寻常性质的液体，其具有许多潜在的应用，例如在所谓的“绿色化学”中或在能量应用中。许多离子液体，由于其两亲性分子结构，倾向于在介观尺度上显示自组装和结构形成（即形成极性和非极性结构域），这影响了这些材料中的分子动力学和离子传输。本研究的目的是了解离子液体介观结构对电荷传输和分子动力学的影响，特别是离子液体介观结构中电荷传输和结构弛豫的耦合/解耦现象，因此本研究对一系列具有不同极性/非极性结构的离子液体进行了研究（例如，通过改变阳离子的烷基链长度或通过添加少量溶剂来实现）相对于分子动力学和离子传输。在下一步中，计划研究离子凝胶中的Ils。后一种系统是基于离子液体，通过添加各种网络形成剂。在这些材料中，高导电性通常与几乎固体般的机械性能相结合，这使得它们在许多应用中特别有趣。在离子凝胶的IL结构的形成和动力学和电荷传输的内表面的效果是要澄清的。特别地，当网络形成剂的几何构型的长度尺度满足IL中的域和聚集体的长度尺度时，预期有趣的效果。在实验方法方面，目前项目的重点是去偏振动态光散射，它明确地识别分子的重新取向，不受电荷传输或偏振效应的影响。不同的光散射技术（光子相关，串联法布里-珀罗和拉曼光谱）的组合使我们能够覆盖整个相关的光谱范围，在1兆赫至约10太赫兹。与此同时，宽带介电谱（1 Microherz和50 GHz之间）将提供有关系统中电荷传输的信息。这样就有可能明确地将分子动力学和电荷输运分开。离子液体中的温度依赖的畴结构将被监测的小角散射技术。 因此，我们希望提高我们的理解的结构形成，动力学和电荷传输的相互关系，在离子液体和离子凝胶，这从长远来看，将有助于实现知识为基础的材料设计与离子液体。