Extremely Long Chains of Magnetic Particles via Large Plastic Beads Observed in Bimodal Magnetic Elastomers
Extremely Long Chains of Magnetic Particles via Large Plastic Beads Observed in Bimodal Magnetic Elastomers
复制标题
在双峰磁性弹性体中观察到通过大塑料珠的极长磁性粒子链
DOI：
10.1021/acs.langmuir.3c00150
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发表时间：
2023
期刊：
影响因子：
3.9
通讯作者：
Mitsumata Tetsu
中科院分区：
文献类型：
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作者：
Urano Rio;Chen Kejun;Akama Shota;Takeda Yoshihiro;Maruyama Takayuki;Suzuki Motohiro;Takeuchi Akihisa;Uesugi Masayuki;Kawai Mika;Mitsumata Tetsu
研究了高浓度（60vol%）的8 μm和200 μm塑料珠的双峰磁性弹性体的磁流变性与颗粒的介观结构之间的关系。动态粘弹性测试结果表明，在370 mT磁场下，粒径为200 μm的双峰弹性体的储能模量变化为2.8 × 105 Pa。不含珠粒的单峰弹性体的储能模量变化为4.9 × 104 Pa。具有8 μm珠粒的双峰弹性体几乎不响应磁场。使用同步辐射X射线CT对颗粒形貌进行了原位观察。对于具有200 μm珠粒的双峰弹性体，当施加磁场时，在珠粒之间的间隙中观察到磁性颗粒的高度排列结构。另一方面，对于具有8 μm珠粒的双峰弹性体，没有观察到磁性颗粒的链结构。通过三维图像分析确定磁性颗粒聚集体的长轴与磁场方向之间的取向角。在磁场作用下，200 μm微珠的取向角为56° ~ 11°，8 μm微珠的取向角为64° ~ 49°。不含珠粒的单峰弹性体的取向角从63°变为21°。结果表明，粒径为200 μm的磁珠能使磁性颗粒链发生连接，而粒径为8 μm的磁珠则阻止磁性颗粒链的形成。
The relationship between the magnetorheology of bimodal magnetic elastomers with high concentrations (60 vol %) of plastic beads with diameters of 8 or 200 μm and the meso-structure of the particles was investigated. Dynamic viscoelasticity measurements revealed that the change in storage modulus of the bimodal elastomer with 200 μm beads was 2.8 × 105Pa at a magnetic field of 370 mT. The change in the storage modulus for monomodal elastomer without beads was 4.9 × 104Pa. The bimodal elastomer with 8 μm beads hardly responded to the magnetic field. In-situ observation for the particle morphology was performed using synchrotron X-ray CT. For the bimodal elastomer with 200 μm beads, a highly aligned structure of magnetic particles was observed in the gaps between the beads when the magnetic field was applied. On the other hand, for the bimodal elastomer with 8 μm beads, no chain structure of magnetic particles was observed. The orientation angle between the long axis of the aggregation of magnetic particles and the magnetic field direction was determined by an image analysis in three dimensions. The orientation angle varied from 56° to 11° for the bimodal elastomer with 200 μm beads and from 64° to 49° for that with 8 μm beads by applying the magnetic field. The orientation angle of the monomodal elastomer without beads changed from 63° to 21°. It was found that the addition of beads with a diameter of 200 μm linked the chains of magnetic particles, while beads with a diameter of 8 μm prevented the chain formation of the magnetic particles.