有机-无机杂化分子基介电开关材料的合成与性能调控研究

Molecular switchable dielectric materials, which can undergo reversible transitions between high and low dielectric states triggered by external stimulus, may be widely used in data communication, signal processing, rewritable optical data storage, etc. At present, molecular switchable dielectrics still do not meet the needs of practical applications because they suffer from the disadvantages of low phase transition temperature, or relatively small change between high and low dielectric states.It is also not very clear how to tune their switchable dielectric properties. In this proposal, organic-inorganic hybrid compounds are designed and prepared by combining polar organic ammoniums easy to be rotated or orientated with metal complex anions. The transitions between high and low dielectric states can be fulfilled due to phase transitions accompanied with dipole changes. The phase transition mechanism will be carefully studied to discolse the dynamic properties of molecular motions during the process of phase transition.Based on the phase transition mechanism, the structures will be systemically tailored in order to investigate the relationship between molecular structures and phase transition temperature, between molecular structures and switchable dielectric properties. At last, it will be obtianed that the mechanism of tuning switchable dielectric properties of molecule-based materials. It is of great importance to engage in this proposal for which could lay the theoretical and practical foundation for the research and development of high-performance molecular switchable dielectric materials, and accelerate its practical application.

分子基介电开关材料能够在外界刺激下实现高低介电状态的可逆转换，在数据通讯、信号处理与传感、可重写光学数据存储等领域有广阔的应用前景。目前得到的分子基介电开关材料存在相变温度偏低，高低介电状态差异偏小等问题，实际应用受到了限制，但是该如何调控介电开关特性响应又缺少必要的理论和实践依据。为此，本项目以有机-无机杂化分子基化合物为研究对象，将易于产生旋转或取向运动的极性有机铵阳离子与金属络合物阴离子结合，利用极性阳离子在相变前后的偶极变化来实现化合物的高低介电状态转换。通过对相变机理的研究，揭示相变过程的微观分子运动机制；结合相变机理系统调控化合物结构，探明化合物结构与相变温度之间的关系，结构与介电开关特性响应之间的关系，获得分子基材料的介电开关性能调控机制。本项目的研究结果有望为研究和开发高性能的分子基介电开关材料提供重要理论依据和实践指导，加快分子基介电开关材料的实际应用进程，具有重要意义。

分子基介电开关材料能够在外界刺激下实现高低介电状态的可逆转换，在数据通讯、信号处理与传感、可重写光学数据存储等领域有广阔的应用前景。本项目针对分子基介电开关材料相变温度偏低，高低介电状态差异偏小等问题，通过系统调变有机铵阳离子结构以及金属络合物阴离子的种类等，合成出了系列新型分子基介电开关化合物，基本上探明了介电开关特性响应与结构之间的关系，阐明了介电开关性能产生的相变机理，能够为开发高性能的分子基介电开关材料提供理论依据和实践指导。在此基础上，我们还发现了一类铁电-介电开关双功能型化合物，可以作为新型多功能材料。此外，我们还利用所制备的分子基介电开关化合物与β-PVDF通过强氢键相互作用进行自组装，研制了取向有序柔性介电开关复合物薄膜，为特定结构的介电开关化合物制备成高性能的复合物薄膜提供了一种简便可行的新方法。