聚离子液基非水聚电解质电流变材料的微波合成与电响应行为研究

Electrorheological (ER) fluid is a smart fluid with electrically tunable rheology, which has many potential uses as electrical–mechanical interfaces for the active control of various devices. However, the practical utilization of ER fluid is still limited by insufficient ER performances. Polyelectrolyte is considered to be one of the most promising commercial ER materials due to its advantages including low density, low abrasive, nontoxicity, relatively high ER activity, etc. However, the classic polyelectrolyte often needs to absorb a quantity of water to promote ionic mobility and thus activate its ER effect. Unfortunately, the presence of water is fraught with the problems associated with evaporation, current leaching, thermal instability, etc., which largely limit the technical application. In this project, to overcome the problems from water-activated ER effect of classic polyelectrolyte, we will develop a new kind of anhydrous polyelectrolyte ER system based on hydrophobic polymeric ionic liquids (PILs) particles by a microwave-assisted dispersion polymerization technique. By a systematical investigation about the local ion transfer, ion transfer-induced interfacial polarization and ER effect of the PIL particles with various molecular structures in the absence of any activators, we will set up the structure-property relationship and disclose the new mechanism behind the ER effect of PIL particles and then propose the molecular structure model for PILs with optimal ER performance. Finally, we will prepare the high-performance PIL-based ER material according to the optimal molecular structure model and obtain the relative process parameters. The successful design and preparation of the novel PIL-based ER system will provide a new way to overcome the shortcomings of water-activated ER effect of classic polyelectrolyte and open a door to develop commercial anhydrous polyelectrolyte-based ER fluid.

电流变液是一种流变性能可被电场调控的智能流体，是实现电力转换最重要的智能驱动材料之一，但由于性能不足制约了它的许多应用。聚电解质因密度低、磨损性小、活性高、无毒等优点是最具实用前景的电流变体系之一，然而传统聚电解质必须依靠水激活离子迁徙来诱导强电流变效应，这导致了蒸发、漏导、热不稳等种种问题且一直无法被有效解决，成为电流变材料领域亟待突破的关键问题之一。本项目开拓一种热稳定的疏水聚离子液基聚电解质电流变材料新体系，突破传统聚电解质必须依靠水激活电流变效应的难题，基于分子设计与微波辅助可控制备，研究分子结构对微观离子输运、宏观极化响应和电流变行为影响规律，建立结构性能关系，揭示聚离子液非水环境下的电流变响应机制，在此基础上确立高电流变活性聚离子液结构预测模型，并通过微波辅助制备技术获得高性能聚离子液电流变材料及宏量可控制备方法，从而为开发实用非水聚电解质电流变液提供材料设计与制备基础。

电流变液是一种可电场调控的智能流体，是实现电力转换最重要驱动材料之一，但性能不足制约了其广泛应用。聚电解质基电流变材料因密度低、磨损小、活性高等优点最具商用前景，然而传统聚电解质必须依靠水激活离子解离迁徙来诱导电流变效应，水的存在会导致材料热稳定和耐久性不佳而限制实际应用，因此如何突破聚电解质电流变必须水激活问题是本领域需解决的关键问题之一。本项目开拓了分子结构本身便疏水的聚离子液基新一代无水聚电解质电流变材料，该材料天然疏水、易于造粒、电流变效应强，典型体系在1000s-1剪切应力0.3kPa@0kV/mm，3.5kPa@3kV/mm；发明了基于复合溶剂的微波辅助分散聚合制备单分散聚离子液电流变颗粒方法；通过聚离子液与离子液比较，揭示了玻璃态环境下离子解离和迁徙诱导的界面极化是聚离子液无水电流变效应的起源；建立了分子结构/聚集态结构-离子局域迁徙-界面极化-电流变性能关系，确定了高电流变活性聚离子液结构设计参数，即聚离子液应具有较短侧链、较小氟化反离子、弱离子对库仑作用、均匀玻璃态基质等；发展出综合性能优化的线型、交联、核壳、纳米复合聚离子液电流变材料及其制备技术。研究结果解决了困扰聚电解质电流变材料必须依靠水激活的问题，为发展新一代实用无水聚电解质电流变液提供了新思路。同时，离子/电子双载流子的核壳聚离子液和Pickering乳液聚合制备的复合聚离子液等为开发高电响应聚离子液基智能材料及电流变应用提供了参考。.该项目在Soft Matter, Macromolecular Rapid Commun., ACS Appl. Polym. Mater., Langmuir, J. Phys. Chem. B, Polymer等杂志发表论文16篇，1篇被选作J. Phys. Chem. B封面。参编英国皇家化学会出版的智能材料丛书中《Polymerized Ionic Liquids》的第6章。论著被美、中、德、韩、英、法、澳、加等多国科学家他引90余次。项目组成员参加国际会议5次（2次邀请报告，3次分会主席或主持人）、国内会议12次（7次邀请报告）。项目负责人受邀赴奥克兰大学化学与材料工程系访问交流。依托该项目培养博士研究生7名（毕业2人），硕士研究生6人（毕业6人）。