Shape Morphing Polymer Networks Based on Ion Gels

非技术总结：聚合物基材料可以经历三维（3D）形状、表面纹理和性能的快速程序化变化，近年来取得了重大进展，为软机器人、触觉界面和适应环境变化或用户需求的自适应材料的发展提供了希望。然而，当前一代材料的性能存在关键限制，这促使了响应性聚合物网络新范式的发展，同时努力提高我们对这些材料在分子和宏观尺度上的理解。目前的项目旨在利用基于离子液体（ILs）的聚合物网络提供的独特优势，离子液体是低熔点（通常低于室温）的盐，具有低挥发性、良好的导电性和稳定性等有用的特性。提出的聚合物和ILs网络可以使形状变形材料的设计取得革命性进展，这些材料可以在广泛的环境条件下工作，并响应低压电气控制信号。通过这项工作开发的基本理解也将与其他情况下的il基聚合物材料相关，包括柔软，柔性和响应性电子设备，或作为电池或燃料电池的膜。该项目将吸引、指导和培训不同层次的参与者，从K-12学生和普通公众，到研究生和博士后研究员，特别强调扩大与马萨诸塞州斯普林菲尔德附近高中生的合作关系。技术概述：虽然形状变形聚合物网络最近取得了快速进展，但最先进的材料仍受到关键限制。例如，刺激响应聚合物水凝胶通常依赖于与周围环境的水交换，限制了水环境的操作，而介电弹性体致动器需要非常高的触发电压（约10 kV）才能起作用。目前的努力旨在利用离子液体（IL）基聚合物材料的特殊性质，特别是其极低的挥发性，高离子电导率和良好的电化学稳定性，以实现新型的响应性和形状变形聚合物网络。在这些目标的推动下，PI将对基于il的聚合物和网络的热力学、响应动力学、力学和电学特性进行基础研究，并展示能够在非水合环境中起作用并响应低压电信号的新型响应材料。除了设计软致动器和形状变形材料的新功能外，所获得的基本理解将与刺激响应材料，膜和离子电子器件中的il基聚合物网络具有广泛的相关性。

NON-TECHNICAL SUMMARY:Polymer-based materials that can undergo rapid programmed changes in three-dimensional (3D) shape, surface texture, and properties have seen major progress in recent years, offering promise for the development of soft robots, tactile interfaces, and adaptive materials that respond to changes in their environment or user needs. However, critical limitations exist on the performance of current-generation materials, motivating the development of new paradigms for responsive polymer networks, alongside efforts to improve our understanding of these materials on both molecular and macroscopic scales. The current project seeks to take advantage of the unique benefits offered by polymer networks based on ionic liquids (ILs), which are salts with low melting points (often below room temperature) that have useful properties including low volatility and good electrical conductivity and stability. The proposed networks of polymers and ILs could enable transformative advances in the design of shape-morphing materials that can operate under a wide range of environmental conditions and in response to low-voltage electrical control signals. The fundamental understanding developed through the work will also hold relevance for IL-based polymer materials in other contexts including soft, flexible, and responsive electronic devices, or as membranes for batteries or fuel cells. The project will engage, mentor, and train a diverse group of participants at a variety of levels ranging from K-12 students and the general public, to graduate students and post-doctoral fellows, with a particular emphasis on expanding a partnership with high-school students in nearby Springfield, MA. TECHNICAL SUMMARY:While shape-morphing polymer networks have seen rapid recent advances, state-of-the-art materials suffer from key limitations. For example, stimuli-responsive polymer hydrogels typically rely on exchange of water with their surroundings, limiting operation to aqueous environments, while dielectric elastomer actuators require very high triggering voltages of ca. 10 kV to function. The current effort seeks to take advantage of the special properties of ionic liquid (IL)-based polymer materials, in particular their very low volatility, high ionic conductivity, and good electrochemical stability, to enable new classes of responsive and shape-morphing polymer networks. Motivated by these goals, the PI will conduct fundamental studies of the thermodynamics, response kinetics, mechanics, and electrical characteristics of IL-based polymers and networks, and demonstrate new types of responsive materials that are capable of functioning in non-hydrated environments and in response to low voltage electrical signals. Alongside the new capabilities for the design of soft actuators and shape morphing materials, the fundamental understanding gained will have broad relevance for IL-based polymer networks in stimuli-responsive materials, membranes, and iontronic devices.