一维层状多组分复合纳米材料的微结构调控及磁性能研究

One-dimensional (1D) magnetic metal nanowires are widely used in fields such as sensors, magnetic recording and medical testing due to their high aspect ratio, vertical magnetic anisotropy, high coercivity and easy magnetization. However, the application of 1D nanowires as integrators in many fields has been affected because of the problem of magnetostatic dipolar interaction, metal oxidation and poor magnetic regulation between densely packed nanowires. For this purpose, the project intends to regulate the magnetostatic dipolar interaction between nanowires by fabricating polymer nanotubes with a method of controlled self-assembly of polymer microstructure. And then, in polymer nanotubes, the magnetic properties of nanowires are controlled by controlling the microstructure of rare earth and ferromagnetic metals to form multilayer nanowires with longitudinal arrangement or coaxial structure. We investigate the molecular shape/structure and physical/chemical properties of polymers that affect and regulate dipolar interaction, reveal the effects of microstructure and synergetic effect on magnetic properties, establish the relationship between microstructure and properties, and develop a research method of “material structure design-microstructure-performance control”. This project aims to take advantage of the physical properties related to the microstructure and properties of objects to develop novel multi-functional nanomaterials, which are expected to be used as integrated materials in medical detection, sensors, magnetic recorders and other fields.

一维磁性金属纳米线因具有高的长径比、良好的垂直磁各向异性、高的矫顽力及易磁化等特点，广泛应用于传感器、磁记录、医疗检测等领域，但紧密堆积的纳米线之间存在静磁偶极作用、金属易氧化及磁性调控性差等问题影响了一维纳米线作为集成体在众多领域中应用。为此，本项目拟通过聚合物微观结构受控自组装形成聚合纳米管调控纳米线间的静磁偶极作用；在聚合物纳米管内，通过控制稀土与铁磁性金属的微观结构形成纵向排列或同轴结构的多层纳米线来调控磁性能。研究聚合物分子形态/结构、物理/化学性质对偶极作用的影响和调控；揭示各级微观结构及协同效应对磁性能的影响规律；建立微观结构-性能的相互关系，发展一种“材料结构设计-微观结构-性能调控”的研究方法。本项目旨在利用物体的微观结构与性能相关这一物理特性，发展新颖的多功能纳米材料，有望将其集成材料应用在医疗检测、传感器及磁记录仪等领域。

一维磁性金属纳米线因具有高纵横比、垂直磁各向异性、高的矫顽力和易磁化等特点而具有广泛的应用领域。但其具有紧密堆积的特点，纳米线之间存在偶极作用，从而降低了纳米线的磁性能，金属纳米线在应用过程中易被氧化，造成磁性能不稳定，限制了其应用。为此，本项目从材料结构入手，设计几种多组分纳米线阵列，通过调整多组分纳米线的结构，研究了纳米线结构与磁性能的关系，从而实现多组分复杂结构的可控组装，建立多层结构—磁性能之间的关系规律。.成功逐层组装了Nd/Ni/PA66三层同轴纳米电缆阵列和不同尺寸Nd/FM（FM=Fe, Co, Ni）双层同轴纳米电缆阵列，结果表明：易磁化轴沿长轴方向。三层纳米电缆的磁性能明显高于单组份铁磁性纳米管的，这是因为聚合物纳米管起到了保护作用并且稀土金属与铁磁金属之间有协同作用。不同尺寸Nd/FM双层同轴纳米电缆阵列平行方向的矫顽力(Hc//)表明：直径为200 nm的纳米电缆比100 nm具有更强的抵抗退磁能力，因此，200 nm的Nd/FM同轴纳米电缆具有硬磁性材料性质。.成功可控地逐层组装了FM-Cu多节纳米线阵列，结果表明： 5个循环纳米线的矫顽力和剩余磁化比(Mr/Ms)要大于2个循环纳米线，这是磁性区域累加的结果。由静磁偶极主导的易磁化轴变为垂直于长轴的方向，多节纳米线同样有明显的磁滞和剩磁现象。.组装了NiCo2O4纳米线，结果表明：多晶结构NiCo2O4纳米线有明显的形状各向异性，并且易磁化轴为平行于长轴的方向，由于氧的参与使易磁化轴Hc//数值增大，垂直方向的矫顽力(Hc⊥)减小。优化的NiCo2O4纳米线作为电极材料展示出优异的比电容和卓越的循环性能。.本项目成功发展了一种能逐层控制微观结构与磁性能可调控的一维多层纳米线结构方法，建立了一种“材料结构设计-微观结构-性能调控”的研究方法。