Size-Dependent Separation of Colloidal Particles In Two-Dimensional Convective Self-Assembly
Size-Dependent Separation of Colloidal Particles In Two-Dimensional Convective Self-Assembly
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DOI：
10.1021/la00008a021
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发表时间：
1995-08
期刊：
影响因子：
3.9
通讯作者：
M. Yamaki;J. Higo;K. Nagayama
中科院分区：
文献类型：
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作者：
M. Yamaki;J. Higo;K. Nagayama
我们报道了一种新的现象，在汞表面上的润湿液膜中发生的二维（2D）对流自组装中胶体颗粒的尺寸依赖性分离[二维（2D）对流组装（Nagayama，K. Phase Transition 1993，45，185）]。在润湿膜中胶体颗粒悬浮液的干燥过程中，悬浮液中均匀混合的颗粒根据其尺寸分离和组装。在这种颗粒的尺寸依赖性分离中，大颗粒聚集在中心，并被小颗粒包围。为了更好地理解这一新现象，我们进行了实验上的对流组装的颗粒在汞表面上使用的二元混合物的颗粒的尺寸范围从144到12纳米的直径。为了研究这种尺寸依赖性分离的机制，我们还进行了计算机模拟，其中我们考虑了两种类型的组装力，横向毛细管力和对流，我们已经在实际组装系统中广泛研究。模拟成功地再现了与实际组装系统相同的颗粒的尺寸依赖性分离。从我们的实验和模拟的结果中，我们发现，该机制得出的对流组装也支配着在实际的组装系统中的颗粒的大小依赖的分离。
We report a new phenomenon, size-dependent separation of colloidal particles in two-dimensional (2D) convective self-assembly that takes place in a wetting liquid film on a mercury surface [Two-dimensional (2D) convective assembly (Nagayama, K. Phase Transition 1993, 45, 185)]. During the drying of suspensions of colloidal particles in wetting films, homogeneously mixed particles in the suspensions separated and assembled according to their size. In this size-dependent separation of particles, large particles gathered in the center and were surrounded by small particles. To obtain a better understanding of this new phenomenon, we performed experiments on the convective assembly of particles on a mercury surface using binary mixtures of particles that ranged in size from 144 to 12 nm in diameter. To study the mechanism of this size-dependent separation, we also did computer simulations in which we accounted for two types of assembly forces, lateral capillary force and convective flow, that we have been extensively studying in actual assembly systems. The simulations successfully reproduced a size-dependent separation of particles that was identical to that for the actual assembly systems. From the results of our experiments and simulations, we found that the mechanism that was concluded for the convective assembly also governs the size-dependent separation of particles in the actual assembly systems.