导电高分子纳米管/金属磁性纳米颗粒复合物新型吸波材料的制备及性能研究

It has become urgent to design and fabricate novel microwave absorbers in order to eliminate or decrease the electromagnetic interference due to the high-frequency circuit devices in wireless communications and radar system.The composites including conducting polymers and magnetic nanoparticles have become a most promising candidate for microwave absorbers in the GHz range due to their high dielectric and magnetic loss.A series of conducting polymer nanotube/ magnetic nanoparticle composites will be designed as novel microwave absorbers and synthesized through chemical self-assembly method.Inside the nanocomposites, metallic magnetic nanoparticles bind and self- assemble on the surface of conducting polymer nanotubes.These nanocomposites maybe obtain a higher shielding effectiveness value since the metallic magnetic nanoparticles can offer high saturation magnetization and conducting polymer nanotubes can offer high conductivity.Metallic magnetic nanoparticles are designed to link to the polymer nanotubes via a coordination bond, which can cause the strong electronic interaction between π-electrons of polymer and d-electrons of magnetic nanoparticles.Changes in the electronic energy levels of nanocomposites make them be able to work in a wider frequency band.The size of conducting polymer nanotubes are further adjusted and modified to improve their solubility, in order to be able to prepare films and devices.This program aims to enhance greatly the microwave absorbing property in GHz range and fulfill the civel and military requirements.It is very necessary for these nanocomposites' fundamental research as well.

为消除高频电子设备产生的电磁波干扰，设计制备新型宽频高效能吸波材料已成为近年来电磁屏蔽领域内一项非常紧迫的任务。本项目拟采用独特的化学自组装方法将金属磁性纳米颗粒键合于导电高分子纳米管表面以制备一系列新型纳米复合吸波剂，兼具高介电常数和磁导率，实现对GHz高频电磁波具有更高的吸波效能；在导电高分子纳米管和金属磁性纳米颗粒之间通过形成化学键引起两种材料之间产生强烈相互作用而使电子能级发生改变，并结合纳米效应以实现进一步拓宽材料的吸波频带；通过对导电高分子纳米管的尺寸进行调节并进行适当的表面化学修饰，以期改善其溶解性，提高加工性能。该项目的实施有望进一步提高导电高分子/磁性纳米颗粒复合材料的吸波效率，满足民用与军工领域对电磁屏蔽的更高需要，并对该类材料的基础研究也有着十分重要的意义

为消除高频电子设备产生的电磁波干扰，设计制备新型宽频高效能吸波材料已成为近年来电磁屏蔽领域内一项非常紧迫的任务。本项目采用独特的化学自组装方法将金属磁性纳米颗粒键合于导电高分子纳米管表面制备出了一系列新型纳米复合吸波剂；然后对导电高分子纳米管/金属磁性纳米颗粒复合物的磁性、电子能带等综合物理性质变化规律及机理进行了深入研究；进而对新型导电高分子纳米管/金属磁性纳米颗粒复合材料的吸波特性的影响因素以及物理机制进行了分析阐释。研究结果显示，导电高分子纳米管在与金属磁性颗粒复合后，其电子能带和磁性都发生了明显改变，结合材料的纳米效应为拓宽其吸波频带，为提高吸波强度提供了条件。研究结果显示，当复合物中的导电高分子纳米管具有更小的管径尺寸时，复合物的吸波强度更大，例如PPy纳米管/CoFe磁性颗粒复合物（20wt%,外径<200 nm）样品的厚度为2.5mm时，在11.98 GHz处反射损耗RL值达到最大，其RLmax为-34.2 dB，明显高于纳米管外径400-450mm的复合物样品，同时有效频宽（-10 dB）为4.56 GHz。该样品在经过真空热处理后最大反射损耗RLmax能进一步提高，增加为-54.4 dB，比退火前增加了约59%，同时其小于-10 dB的频带宽度约为4.36 GHz，而且样品厚度在2mm-5mm之间变化时其最大反射损耗RLmax都大于-30 dB,其最大反射损耗RLmax出现的频率随样品厚度的改变而发生移动。导电高分子/金属磁性纳米颗粒复合物新型吸波材料具有突出的“轻薄宽强”特点，能够满足民用及军工领域对电磁屏蔽材料的更高要求。