Fabrication of novel anisotropic magnetic microparticles
Fabrication of novel anisotropic magnetic microparticles
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DOI：
10.1039/b814971m
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发表时间：
2009-01-01
影响因子：
--
通讯作者：
Paunov, Vesselin N.
中科院分区：
文献类型：
--
作者：
Dyab, Amro K. F.;Ozmen, Mustafa;Paunov, Vesselin N.
我们报告了一种新的技术，用于制造磁各向异性微粒的基础上“逮捕”的油酸涂层的磁铁矿纳米粒子（OCMNs）分散在可聚合的水包油乳液的油滴内的对齐。这是通过在外部磁场存在下使连续水相胶凝后使油滴聚合来实现的。这种方法使我们能够产生具有各向异性光学和磁性的磁性Janus粒子，这些粒子在暴露于外部磁场时形成不寻常的锯齿形链和结构。我们研究了这些新的微粒的磁性能，并表明它们保留了剩磁磁化强度与高磁化率值指示铁磁行为。这表明复合聚合物Janus微粒具有净磁偶极子，并且由于OCMN在其聚合物基质中的“被捕”取向而表现得像微磁体。利用相同的技术，磁性Janus微粒已被制备的基础上稳定的乳液仅由OCMNs不使用表面活性剂，和连续的水相的pH值对这些微粒的形态的影响进行了研究。
We report a novel technique for fabrication of magnetically anisotropic microparticles based on "arresting" of the alignment of oleic acid coated magnetite nanoparticles (OCMNs) dispersed within the oil drops of a polymerisable oil-in-water emulsion. This was achieved by polymerising the oil drops after gelling the continuous aqueous phase in the presence of an external magnetic field. This approach allowed us to produce magnetic Janus particles with anisotropic optical and magnetic properties which form unusual zig-zag chains and structures when exposed to an external magnetic field. We studied the magnetic properties of these novel microparticles and showed that they retained remanence magnetisation with high coercivity values indicative of ferromagnetic behaviour. This indicates that the composite polymeric Janus microparticles posses a net magnetic dipole and behave like micromagnets due to the "arrested" orientation of the OCMNs in their polymeric matrix. Utilizing the same technique, magnetic Janus microparticles have been prepared based on emulsions stabilised only by OCMNs without the use of surfactants, and the effect of pH of continuous aqueous phase on the morphology of these microparticles has been investigated.