Experiments and Simulations on the Magnetorheology of Magnetic Fluid Based on Fe3O4 Hollow Chains.
Experiments and Simulations on the Magnetorheology of Magnetic Fluid Based on Fe3O4 Hollow Chains.
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DOI：
10.1021/acs.langmuir.9b01957
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发表时间：
2019-08
期刊：
影响因子：
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通讯作者：
Lei Pei;Shouhu Xuan;Jie Wu;Linfeng Bai;X. Gong
中科院分区：
文献类型：
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作者：
Lei Pei;Shouhu Xuan;Jie Wu;Linfeng Bai;X. Gong
采用实验/模拟相结合的方法研究了基于Fe 3 O 4空心链的磁流体的磁流变机理。在稀磁流体中，剪切应力随磁场的增加而减小。空心链在小磁场下表现出比纯Fe 3 O 4空心纳米球更高的MR效应。为了更好地理解流变性能与微观结构之间的关系，提出了一种改进的颗粒级模拟方法，该方法考虑了链的平移和旋转运动。在弱外场（24 mT）下形成倾斜的团簇状微结构，而在强外场（240 mT）下观察到垂直的柱状微结构。剪切应力的降低是由于微观结构的强烈重构过程和链在边界附近的聚集。链状结构的出现增加了微结构的倾角，从而改善了弱场下的磁流变效应。这一优点使得Fe 3 O 4空心链在生物医学领域被广泛应用于小型和低功耗器件。无粘性粘度作为Mason数的函数被压缩到线性主曲线上。对磁流体在微流通道内Poietille流中的快拍现象进行了观察和模拟。模拟和实验之间的定性和定量的对应关系。
This work reported an experiment/simulation combining study on the magnetorheological (MR) mechanism of magnetic fluid based on Fe3O4 hollow chains. The decrease of shear stress versus increasing magnetic field was observed in a dilute magnetic fluid. Hollow chains exhibited higher MR effect compared to pure Fe3O4 hollow nanospheres under a small magnetic field. A modified particle level simulation method including the translational and rotational motion of chains was developed to comprehend the correlation between rheological properties and microstructures. Sloping cluster-like microstructures were formed under a weak external field (24 mT) while vertical column-like microstructures were observed under a strong field (240 mT). The decrease of shear stress was due to the strong reconstruction process of microstructures and the agglomeration of chains near the boundaries. The chain morphology increased the dip angle of microstructures and thus improved the MR effect under a weak field. This advantage made Fe3O4 hollow chains widely applied for small and low-power devices in the biomedical field. Dimensionless viscosity as a function of Mason number was collapsed onto linear master curves. The snapshots of magnetic fluid in Poiseuille flow in a microfluidic channel was also observed and simulated. A qualitative and quantitative correspondence between simulations and experiments was obtained.