Characterization on magnetophoretic velocity of the cluster of submicron-sized composite particles applicable to magnetic separation and purification
Characterization on magnetophoretic velocity of the cluster of submicron-sized composite particles applicable to magnetic separation and purification
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DOI：
10.1016/j.colsurfa.2019.02.011
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发表时间：
2019-05-05
影响因子：
5.2
通讯作者：
Nagao, Daisuke
中科院分区：
文献类型：
--
作者：
Kohama, Natsuki;Suwabe, Chika;Nagao, Daisuke
制备了亚微米级低分散性磁性复合粒子，研究了复合粒子在磁场作用下的磁泳速度与团聚状态的关系。采用尺寸范围为70-470 nm的五种不同的磁性复合颗粒来测量磁泳速度。由于最小的复合颗粒具有不足以测量磁泳速度的胶体稳定性，因此在磁场下用光学显微镜观察其余的复合颗粒。大于300 nm的磁性复合粒子在磁场作用下形成了磁性复合粒子的珍珠链。珠链的运动速度随珠链中复合颗粒的数量而增加。采用珍珠链速度与单个复合颗粒速度之比来定量描述复合颗粒聚集时磁泳速度的增加。大颗粒的速度比是在良好的协议与理论的一个与珍珠链中的复合颗粒的数量。另一方面，小于200 nm的复合颗粒形成复合颗粒的随机簇。由于用光学显微镜不能直接观察到单个小颗粒，因此假设小复合颗粒形成具有0.64的随机填充因子的椭圆形状，估计簇中的小复合颗粒的数量。与大颗粒复合物相似，小颗粒复合物的聚集也增加了由小颗粒复合物组成的随机团簇的速度比。不同复合颗粒之间的速度比的比较表明，小颗粒的集群有一种趋势，表现出的速度比高于大颗粒。一个很好的相关性的速度比与估计的复合颗粒在一个集群中的数量显示，复合颗粒的数量是一个重要的因素，以量化的随机集群的磁泳速度。
Submicron-sized magnetic composite particles with low polydispersity were prepared to examine the relation between the magnetophoretic velocity and the clustering state of composite particles under application of magnetic field. Five different magnetic composite particles in a size range of 70-470 nm were employed to measure the magnetophoretic velocity. Since the smallest composite particles had colloidal stability insufficient to measure the magnetophoretic velocity, the rest of composite particles was observed with an optical microscope under a magnetic field. Magnetic composite particles larger than 300 nm formed pearl chains of magnetic composite particles under the magnetic field. The velocity of pearl chains was increased by the number of composite particles in a pearl chain. The ratio of the velocity of pearl chain to that of a single composite particle was employed to quantify the increase in magnetophoretic velocity with the clustering of composite particles. The velocity ratio for the large particles was in good agreement with the theoretical one correlated with the number of composite particles in a pearl chain. On the other hand, composite particles smaller than 200 nm formed random clusters of composite particles. Since a single small particle could not be directly observed with the optical microscope, the number of small composite particles in a cluster was estimated with an assumption that the small composite particles formed an ellipsoidal shape with a random filling factor of 0.64. Similarly to the large composite particles, the velocity ratio of random clusters composed of the small composite particles was also increased by clustering the small MCPs. Comparison of the velocity ratios between different composite particles indicated that the clusters of small particles have a tendency of exhibiting velocity ratios higher than that of large particles. A good correlation of the velocity ratio with the estimated number of composite particles in a cluster revealed that the number of composite particles is an important factor to quantify the magnetophoretic velocity of random clusters.