导电聚合物@碳包裹板状磁性纳米胶囊制备及微波吸收性能研究

The nanocapsules with shell/shell/core structure as new types of microwave absorbing materials have been favored. In this project, carbon-coated flake-shaped magnetic nanocapsules will be prepared by plasma arc discharge method, and then the conducting polymer will be introduced to encapsulate the nanocapsules using the chemical polymerization method; at last, a new type of conducting polymer @ carbon coated flake-shaped magnetic nanocapsules with double shell microstructure will be synthesized after filtration and drying process. The existence of conducting polymer shell-carbon shell interface enhances kinds of dielectric loss, and the flake-shaped magnetic core adjusts the anisotropy and complex permeability in conducting polymer @ carbon coated flake-shaped magnetic nanocapsules; the mechanism of dielectric loss will be further explained and the anisotropic model will be optimized; the relationship between the dielectric properties and interface structure of the nanocapsules will be performed; the relationship between the magnetic properties and structure together with size of the magnetic core will be studied; the influence of complex permittivity and complex permeability with frequency on the microwave absorbing properties will be deeply analyzed; The relationship between microstructure and microwave absorbing properties based on the results of this project will be revealed for guiding the design and synthesis of novel microwave absorbing materials.

具有壳/壳/核结构的纳米胶囊作为一种新型微波吸收材料正倍受青睐。本项目将利用等离子电弧放电法制备碳包裹板状磁性纳米胶囊，利用化学聚合法引入导电聚合物包裹纳米胶囊，经过过滤和干燥等过程，得到具有新颖双壳层微观结构的导电聚合物@碳包裹板状磁性纳米胶囊。导电聚合物壳-碳壳界面丰富了纳米胶囊的介电损耗类型，板状磁性内核调整纳米胶囊的各向异性和复磁导率。我们将进一步解释介电损耗机理，并且完善各向异性模型；调查纳米胶囊的介电性能与界面结构之间的关系; 研究纳米胶囊的磁性能与磁性内核结构和尺寸之间的关系；深入分析复介电系数和复磁导率随频率变化对微波吸收性能的影响。通过以上的研究以期揭示微观结构和微波吸收性能之间的关系，并以此为指导设计合成新型微波吸收材料。

本项目是研究聚苯胺和碳外壳对磁性纳米颗粒面向微波吸收应用中存在的关键科学和基础问题。利用直流电弧放电法在Ar和H2气氛下引入乙醇制备了Fe@C和Ni@C纳米胶囊。通过X-射线衍射仪(XRD)和高分辨透射电子显微镜(HRTEM)对其相组成和微观结构进行表征，使用网络矢量分析仪对其2-18GH范围内的复介电常数和复磁导率进行了测量。通过对石墨外壳对Fe纳米颗粒的热学、磁性和电磁性能的影响被详细研究，发现石墨外壳能有效地抑制Fe纳米颗粒的生长、提高Fe纳米颗粒的热稳定性并且通过核-壳界面处的电磁匹配增强Fe纳米颗粒的电磁吸收能力。通过对具有相似厚度石墨外壳的不同尺寸Ni@C纳米胶囊的电磁性能深入研究，发现其介电损耗随颗粒尺寸变大而降低，同时随着尺寸降低，最佳RL值将在更薄的吸收厚度处取得且具有更宽的吸收频带。在Fe3O4纳米颗粒表面通过化学原位聚合法引入聚苯胺(PANI)合成Fe3O4@PANI纳米胶囊。通过对其电磁吸收性能的计算，发现聚苯胺能有效提高其介电损耗能力，同时扩展了其吸收频宽。为了研究界面对介电性能的影响，在Ni@C纳米胶囊表面引入Ag3PO4纳米颗粒进行修饰，并其对产物进行了电磁参数研究。发现复磁导率没有变化，而介电常数的实部和虚部都增大。通过这些研究工作，发表了SCI收录论文34 篇，授权国家发明专利6 项，并为具有聚苯胺和碳外壳的磁性纳米胶囊电磁吸收材料的研究提高了实验支持和理论依据。