Fabrication of One-Dimensional Iron Oxide/Silica Nanostructures with High Magnetic Sensitivity by Dipole-Directed Self-Assembly
Fabrication of One-Dimensional Iron Oxide/Silica Nanostructures with High Magnetic Sensitivity by Dipole-Directed Self-Assembly
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DOI：
10.1021/jp804452r
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发表时间：
2008-09
影响因子：
3.7
通讯作者：
Feng Zhang;Changchun Wang
中科院分区：
文献类型：
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作者：
Feng Zhang;Changchun Wang
通过高温水解反应制备了粒径分布较窄的弱铁磁性纳米氧化铁。磁性纳米颗粒可以在没有外加磁场的情况下，通过磁偶极相互作用在基质上自组装成一维颗粒链，也可以在胶体分散中自组装。进一步利用这些一维组件制备了一维纳米结构，其中磁性纳米颗粒包裹体排列整齐，并且具有连续的二氧化硅外壳。通过磁性纳米粒子在乙醇、氨和水的混合物中的链状自组装，然后在组装的表面进行正硅酸乙酯的Sol−凝胶过程，制备了一维氧化铁/二氧化硅纳米结构。纳米结构的长度可以通过超声的幅度来控制，二氧化硅涂层的厚度可以通过TEOS的用量来调节。一维纳米结构显示出很高的磁敏性。在外加磁场存在的情况下，纳米结构...
Weakly ferromagnetic iron oxide nanoparticles with narrow size distribution were prepared by a high-temperature hydrolysis reaction. The magnetic nanoparticles can self-assemble into one-dimensional particle chains on substrates as well as in colloid dispersion through magnetic dipolar interaction without the help of an applied magnetic field. The 1D assemblies were further harnessed to prepare 1D nanostructures with aligned magnetic nanoparticle inclusions and a continuous silica shell. One-dimensional iron oxide/silica nanostructures were prepared through chainlike self-assembly of the magnetic nanoparticles in a mixture of ethanol, ammonia, and water followed by a sol−gel process of TEOS at the surface of the assemblies. The length of the nanostructures can be controlled by the amplitude of ultrasonication, and the thickness of the silica coating can be tuned by the dosage of TEOS. The 1D nanostructures exhibit highly magnetic sensitivity. In the presence of an applied magnetic field, the nanostructure...