具有电子/离子双载流子的共轭聚离子液的界面极化与电流变效应研究

Electrorheological (ER) fluid is a kind of soft smart material with electrically tunable rheology, which has many potential uses as electrical–mechanical interfaces with high efficiency and low power consumption. However, the large scale of practical applications of ER fluid is limited by insufficient ER performances. Polyelectrolyte is one of the most important ER active systems. Recent research of using hydrophobic polymeric ionic liquids (PILs) particles as electroactive component has led new way to develop high performance anhydrous polyelectrolyte-based ER fluid, which can well overcome the problems associated with water-containing classic polyelectrolyte ER fluid. Due to high activation energy of ionic transport, however, the ER effect of PIL-based ER fluid has to subject to strong temperature dependence that is not desired in the real application. In this project, we propose a new strategy to overcome the strong temperature sensitivity of ER effect of PIL system by introducing conjugated main backbone into PIL molecule and develop a new kind of anhydrous conjugated PIL ER system that has a mixed electronic and ionic transport. By combining low-activation-energy electronic transport and high-activation-energy ionic transport, an achievable interfacial polarization in wide temperature region is expected to be achieved. As a result, the conjugated PILs can exhibit not only stronger ER effect but also more stable temperature dependence of ER effect in wide temperature region when compared to present non-conjugated PIL systems. By the rheological and dielectric relaxation study, we will understand the mechanism behind enhanced ER performances of conjugated PILs and their structure-property relationship and accordingly provide a new way to design and prepare new generation of anhydrous polyelectrolyte-based ER fluid with versatile performances.

电流变液是一种流变性能可电场调控的智能软材料，用它可实现高效节能的电力转换，但性能不足制约了其应用。聚电解质是最重要的电流变材料之一，而最近开发的聚离子液非水聚电解质电流变材料突破了传统聚电解质的电流变效应对水的依赖难题，为开拓新一代实用非水聚电解质电流变液提供了基础。然而，由于大尺寸离子作载流子所固有的高迁徙活化能导致聚离子液的极化响应和电流变效应的温度敏感问题仍需有效解决。针对此，本项目拟发展一种具有电子/离子双载流子的共轭聚离子液电流变新体系，通过协同低迁徙活化能电子和高迁徙活化能离子的局域迁徙实现宽温区有效极化响应，解决目前依靠单一离子迁徙模式极化的聚离子液电流变性能的温度敏感问题。结合结构调控、流变测试和介电谱分析，揭示电子/离子双载流子模式下电流变效应强化与温度依赖性优化的物理机制，建立结构与性能优化关联，为开发综合性能优异的非水聚电解质电流变液提供材料设计新方法。

电流变液是一种流变性能可电场调控的智能软材料，用它可实现高效节能的电力转换，但性能不足制约了其应用。聚电解质是最重要的电流变材料之一，而最近开发的聚离子液非水聚电解质电流变材料突破了传统聚电解质电流变效应对水的依赖难题，为开拓新一代实用聚电解质电流变液提供了基础。然而，由于离子作载流子所固有的高迁徙活化能导致聚电解质，特别是聚离子液的极化响应和电流变效应的温度敏感问题仍需有效解决。针对这些问题，本项目：（1）发展了可将无规PIL粉末转化成均匀的微米级PIL微球的非化学新方法，包括冷却辅助相分离（CAPS）方法和蒸发辅助相分离（EAPS）方法。（2）发展了制备无机增强PIL空心微球的受限的冷却辅助相分离新方法，解决了依靠单一PIL电流变性能温度敏感问题。（3）揭示了分子量、离子对结构对PIL的离子迁徙、界面极化及电流变效应的影响规律。（4）发展出高热稳定的自交联PIL电流变新体系，揭示了其结构性能关系。（5）设计制备了具有电子/离子双载流子共轭PIL电流变材料体系，揭示了电子/离子双载流子迁徙模式下电子-离子耦合效应对颗粒介电极化强度与高温电流变效应的提升的促进作用。（6）制备出具有电子/离子双载流子迁徙模式的聚离子液/聚苯胺共混复合颗粒，证实了双载流子诱导的界面极化速率匹配度对电流变效应和温度稳定性的作用。.该项目在Macromolecular Rapid Commun., J. Phys. Chem. B, European Polymer J., Polymer, ACS Appl. Polym. Mater.等杂志发表论文24篇，1篇论文被选作Macromolecular Chemistry and Physics封面文章，1篇被选为J. Phys. Chem. B补充封面文章。论文被中国、美国、日本、瑞典、西班牙、加拿大、俄罗斯、波兰、捷克、印度等科学家SCI他引120余次。项目主持人尹剑波被选为IAAM Fellow。项目组成员国内会议3次（3次邀请报告）。依托该项目培养博士研究生7名（毕业3人），硕士研究生4人（毕业4人）。