金属/碳纳米胶囊微结构调控及微波频段电致多重介电极化效应研究

Metal/carbon-composed nanocapsules have been proven promising potentials as microwave absorption materials ascribed to the proper electromagnetic matching resulted from an effective combination of heterogeneous magnetic/dielectric components and nanoscale microstructures. However, microwave absorbers are usually designed to solve electromagnetic interferences at a specific frequency, while the requirements may be dynamic during service life. In this proposal, we plan to synthesize the metal/carbon-composed nanocapsules with multimodal dielectric polarizations by optimizing the defective concentration and variety of graphic shells, and the heterogeneous interfaces at nano/sub-nano-scale. In particular through an external electric field coupling these multimodal polarized sites would be further adjusted in order to manipulate the polarization strength, the orientation and the resonant frequency. Based on the classic electron conduction theory and the micromagnetic theory, we would further focus on the understanding of the relationship between the electric-field and the multimodal polarization, the complex permeability, the complex permittivity and the loss factors, as well as the uncovering of their physical mechanisms and the microstructural origins.

磁/介复合型金属/碳纳米胶囊材料因其微结构和成分的电磁匹配构造，展示出优异的宽频段微波吸收特性。然而，一旦其结构、成分给定，其吸波性能也就确定，从而难以适应复杂多变电磁环境的需求。本课题拟通过调控碳壳缺陷密度、种类以及纳米/亚纳米尺度异质界面等，获得金属/碳纳米胶囊的多重介电极化效应。尤其是利用外加电场耦合作用实现对介电极化位点的强度、取向、共振频率等的可逆调控，获得“动态”介电极化和微波吸收特性。进一步，以电子传导理论和微磁学理论阐明外电场协同多重极化效应与复磁导率、复介电常数、和损耗因子等参数之关联，进而探究电场调控纳米胶囊微波吸收的物理机理和结构本源。

本课题以磁/介复合型金属/碳纳米胶囊材料为主要研究对象，研究利用多物理场调控材料介电极化效应，以实现材料电磁波吸收特性的有效调控。利用等离子体电弧放电技术设计制备了铁/碳纳米胶囊，利用外加电场对材料介电极化强度进行调控。研究表明，外电场能够增强金属与碳壳，碳壳间界面多重极化强度，进而促进材料与电磁波相互作用，增加吸收损耗。利用非晶碳和氧化石墨材料设计制备了碳基忆阻器件，发展了光辅助还原和恒电流预制等方法，实现了碳材料中sp2/sp3杂化态的有效调控。研究表明，以团簇形式存在的sp2杂化态能够有效增强薄膜内部的局域电场分布，诱导离子迁移，简化导电通道形成路径，有效提升碳基材料的忆阻可靠性。项目研究取得一系列研究成果，发表SCI论文17篇，申请/授权发明专利4项，完成计划书约定目标，为发展智能型碳基微波吸收材料和碳基忆阻材料提供了技术储备。