多形貌Ag@MxOy核壳微纳粒子增强聚合物介电性能的微观机制及其功能调控

The main objective of this research project is to construct a novel multi-morphology, multi-size core shell structural micro/nano-particles with Ag as core and inorganic oxide as shells. By adjusting the synthesis parameters, the growth driving force of Ag core and the sedimentary micro environment of inorganic oxide shells are controlled and the core-shell structures of particles with multi-morphology and multi-size are also effectively regulated. This kind of core-shell particles will be doped in situ into polymer to fabricate the composites with enhanced dielectric properties. The intrinsic connections between the morphology, size, orientation and distribution of the Ag@MxOy particles and the microstructural evolution and internal dielectric percolation relation network morphology of composites are systemly investigated. The broadband dielectric properties of composites were tested, the mechanism of the abruptly changing in the dielectric properties of the composites when percolated was analysized. Moreover, the effects of Ag@MxOy core-shell particles on the carriers’ polarization characteristics in polymers were also investigated. Then the dielectric enhancement model of the Ag@MxOy/polymer composites was established and the micro-mechanism of the dielectric enhancement was revealed. Based on the reasonable design and control of the dielectric percolation network, the effective control of the dielectric properties of the composites is realized. The expected results of this project will further enrich the effective controlling methods on dielectric properties for polymer matrix composites, then promote the development of high energy density of polymer engineering dielectric composites.

本项目拟在微纳米尺度下对不同形貌、尺寸的金属银粒子进行表面无机氧化物包覆，构筑具有多形貌、多尺寸特征的Ag@MxOy核壳微纳粒子。控制Ag“核”的生长驱动力及MxOy “壳”包覆过程的微区环境，实现对Ag@MxOy粒子形貌、尺寸的有效调控。制备Ag@MxOy/聚合物复合材料，通过调整Ag@MxOy粒子含量及复合材料制备工艺，构建介电逾渗网络；系统研究Ag@MxOy粒子的形貌、尺寸特征及其取向、分布情况对复合材料微结构及介电逾渗网络形态的影响；测试复合材料的介电特性，分析渗流时材料介电性能发生突变的机理，探讨Ag@MxOy粒子的逾渗效应对复合材料介电性能的影响，建立介电增强模型，揭示复合材料介电增强的微观机制；通过对介电逾渗网络形态的合理设计及控制，实现复合材料介电性能的有效调控。本项目的研究成果将会进一步丰富聚合物基复合材料介电性能的有效调控方法，推动高储能密度工程电介质材料的发展。

本项目针对多形貌Ag@MxOy核壳粒子的制备及其对聚合物介电增强的微观机理开展了深入研究。具体包括如下内容：1）以金属银(Ag+)离子溶液为初始物质，采用液相合成法，通过调控反应介质种类、浓度、配比，反应温度、时间等因素实现了对Ag粒子形貌、尺寸的有效控制，制备出具有球状、棒状、线状且尺寸多样的纳米Ag粒子。在此基础上，利用受控的表面沉积反应在Ag粒子表面包覆了多种不同成分的绝缘层，具体为无机绝缘体SiO2、无机绝缘体Al2O3、无机半导体ZnO和有机半导体PDA层。2）采用机械搅拌结合超声分散的方式，将所制备的不同类型Ag@MxOy核壳粒子引入聚偏氟乙烯中，通过调整Ag@MxOy的含量，构建Ag@MxOy核壳粒子在聚合物中的介电逾渗网络。3）深入分析了Ag@MxOy核壳粒子对聚合物微结构演变及介电逾渗网络形态的影响及其规律，发现Ag@shell纳米棒在PVDF基体中具有良好的分散性，其中有机包覆层比无机包覆层表现出与基体PVDF更好相容性。XRD和FT-IR分析表明与Ag纳米棒相比，Ag@shell核壳纳米棒的负载能有效地诱导PVDF相从α转变为β和γ相，使得复合薄膜的极化能力显著提高。4）结合复合材料的介电特性测试结果，深入分析了Ag@MxOy核壳粒子的渗流效应对复合材料介电损耗的影响及MxOy壳层对漏导电流的阻隔效应，构建了介电增强模型，揭示了复合材料介电增强的微观机制。通过本项目的实施，开发并掌握了不同形貌Ag@MxOy纳米粒子的核壳结构设计及调控方法，获得了Ag@MxOy核壳粒子对聚合物的介电增强机理，形成了创新性成果。共发表学术论文16篇，其中SCI收录16篇。授权国家发明专利1项，获黑龙江省科学技术三等奖（自然类）1项，参加国际学术会议4人次，培养了4名硕士研究生并已取得硕士学位，另有2人正在攻读博士学位，3人正在攻读硕士学位。