Shape Morphing Polymer Networks Based on Ion Gels

近年来，能够在三维（3D）形状、表面纹理和性能方面进行快速编程变化的聚合物基材料取得了重大进展，为开发软机器人、触觉界面和适应环境或用户需求变化的自适应材料提供了希望。然而，当前一代材料的性能存在关键限制，这促使开发响应性聚合物网络的新范例，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（IL）的聚合物网络提供的独特优势，离子液体是具有低熔点（通常低于室温）的盐，具有低挥发性和良好的导电性和稳定性等有用特性。 所提出的聚合物和离子液体网络可以使形状变形材料的设计取得变革性进展，这些材料可以在广泛的环境条件下工作，并响应低压电控制信号。通过这项工作开发的基本理解也将与其他背景下的IL基聚合物材料相关，包括柔软，灵活和响应的电子设备，或作为电池或燃料电池的膜。该项目将参与，指导和培训不同层次的参与者，从K-12学生和公众，到研究生和博士后研究员，特别强调扩大与附近斯普林菲尔德的高中生的伙伴关系，MA。技术概述：虽然形状变形聚合物网络最近取得了快速进展，但最先进的材料受到关键限制。例如，刺激响应性聚合物水凝胶通常依赖于水与其周围环境的交换，将操作限制在水性环境中，而介电弹性体致动器需要非常高的触发电压，约为20 V。10 kV运行。目前的努力试图利用离子液体（IL）基聚合物材料的特殊性质，特别是它们非常低的挥发性、高离子电导率和良好的电化学稳定性，以实现新类别的响应性和形状变形聚合物网络。在这些目标的推动下，PI将进行基于IL的聚合物和网络的热力学，响应动力学，力学和电气特性的基础研究，并展示能够在非水合环境中发挥作用并响应低压电信号的新型响应材料。 除了软致动器和形状变形材料设计的新能力之外，所获得的基本理解将对基于IL的聚合物网络在刺激响应材料，膜和离子电子器件中具有广泛的相关性。

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.