基于界面区载荷传递效率增强设计的柔性多铁复合材料磁电耦合性能与机理研究

As a typical kind of multi-functional dielectric, multiferroic magnetoelectric (ME) material has a great potential for application in the fields of magnetic sensor, transducer, tunable microwave devices and information storage device. This project aims at the problem of low magnetoelectric properties induced by the large difference of elastic modulus between two phase materials in flexible multiferroic composites. A plasma enhanced chemical vapor deposition (PECVD) method is used to in-situ fabricate carbon nanotubes (CNT) on the surface of ferromagnetic particles. The "sea cucumber-like" ferromagnetic composite particles are achieved. The interfacial region of composites can be regulated by controlling the structure parameters of CNT such as morphology, size and so on. Then, the loading transfer efficiency between the matrix and the ferromagnetic particles and magnetoelectric properties will be improved. Moreover, microstructure evolution information of matrix and interfacial region in the composites is detected by synchrotron radiation techniques, etc. Based on the results of characterization and simulation, the constitutive relation for the coupling magnetic-mechanical-electrical interactions in the composites with "sea cucumber-like" particles is constructed. The relationship between the interfacial region and the electrical, magnetic, magnetoelectric properties of the composites is revealed. The mechanism related to interfacial region regulating magnetoelectric properties of the composites will be proposed. This project will provide theoretical and experimental basis for the preparation and performance optimization of polymer based multifunctional composites. A new kind of flexible multiferroic composites with excellent magnetoelectric properties can be expected.

多铁复合材料作为一类多功能介质，在磁传感器、换能器、可调微波器件和信息存储器件中有广阔应用前景。本项目针对柔性多铁复合材料中，由于两相材料弹性模量相差较大而造成磁电耦合性能偏低的问题，计划利用等离子体增强化学气相沉积方法在铁磁颗粒表面原位生长碳纳米管，制备“海参状”铁磁复合颗粒；通过碳纳米管的形貌和尺寸等结构参量控制复合材料的界面区结构，进而提高两相间的载荷传递效率和材料的磁电耦合性能；并利用同步辐射等技术探测复合材料中基体与界面区的微观结构演化信息；基于表征与模拟仿真结果，构建含有“海参状”填充相(夹杂)的复合材料的磁-力-电耦合本构关系；全方位、多角度、深入系统地揭示界面区结构设计与复合材料电、磁、磁电耦合性能关联性的相关规律；阐明界面区结构对复合材料磁电耦合性能的调控机理，为聚合物基多功能复合材料制备与性能优化提供理论与实验依据，以期获得高磁电耦合性能的新型柔性多铁复合材料。

多铁复合材料作为一类多功能介质，在磁传感器、换能器、可调微波器件和信息存储器件中有广阔应用前景。本项目主要针对柔性多铁复合材料中由于两相材料弹性模量相差较大而造成磁电耦合性能偏低的问题，首先设计并成功制备了核壳结构、类海参状铁磁复合填料，探明了制备钴铁氧体纤维与在其表面包覆壳层的技术参数；其次，为了在提高铁磁填料含量的同时保证其铁电特性，利用高速定向纺丝技术获得拥有高度取向化铁磁填料的聚偏氟乙烯-三氟乙烯基柔性多铁复合材料，并获得关键技术参数；再次，通过调控壳结构参量控制复合材料的界面区结构，利用钴铁氧体纤维表面钛酸钡包覆层的压电性进而提高两相间的载荷传递效率和材料的磁电耦合性能；此外，在铁磁填料均一填充复合材料中存在漏电流大、铁电性能下降现象，从而导致磁电耦合性能降低，基于此设计了“三明治”结构的复合材料，填料在复合材料中分布的非均一性有效地改善了复合材料漏电流大、难以极化的问题；基于表征与模拟仿真结果，全方位、多角度、深入系统地揭示界面区结构设计/填料三维分布设计与复合材料电、磁、磁电耦合性能关联性的相关规律；阐明界面区结构对复合材料磁电耦合性能的调控机理，为聚合物基多功能复合材料制备与性能优化提供理论与实验依据，最终获得了高磁电耦合性能的新型柔性多铁复合材料。