Magnetic Assembly and Cross-Linking of Nanoparticles for Releasable Magnetic Microstructures

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• 作者：Camilo Velez ; Isaac Torres-D铆az ; Lorena Maldonado-Camargo ; Carlos Rinaldi ; David P. Arnold
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：October 27, 2015
• 年：2015
• 卷：9
• 期：10
• 页码：10165-10172
• 全文大小：506K
• ISSN：1936-086X

文摘

This article describes a versatile method to fabricate magnetic microstructures with complex two-dimensional geometric shapes using magnetically assembled iron oxide (Fe₃O₄) and cobalt ferrite (CoFe₂O₄) nanoparticles. Magnetic pole patterns are imprinted into magnetizable media, onto which magnetic nanoparticles are assembled from a colloidal suspension into defined shapes via the shaped magnetic field gradients. The kinetics of this assembly process are studied by evaluation of the microstructure features (e.g., line width and height) as a function of time, particle type, and volume fraction. After assembly, the iron oxide particles are cross-linked in situ and subsequently released by dissolving a sacrificial layer. The free-floating magnetic structures are shown to retain their patterned shape during manipulation with external magnetic fields.