Xie Qingguang, Harting Jens
Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600MB, Eindhoven, The Netherlands.
Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Forschungszentrum Jülich, Fürther Str. 248, 90429, Nürnberg, Germany.
Adv Mater. 2021 Feb;33(8):e2006390. doi: 10.1002/adma.202006390. Epub 2021 Jan 14.
Colloidal assembly at fluid interfaces has a great potential for the bottom-up fabrication of novel structured materials. However, challenges remain in realizing controllable and tunable assembly of particles into diverse structures. Herein, the capillary assembly of magnetic ellipsoidal Janus particles at a fluid-fluid interface is reported. Depending on their tilt angle, that is, the angle the particle main axis forms with the fluid interface, these particles deform the interface and generate capillary dipoles or hexapoles. Driven by capillary interactions, multiple particles thus assemble into chain-, hexagonal-lattice-, and ring-like structures, which can be actively controlled by applying an external magnetic field. A field-strength phase diagram is predicted in which various structures are present as stable states. Owing to the diversity, controllability, and tunability of assembled structures, magnetic ellipsoidal Janus particles at fluid interfaces could therefore serve as versatile building blocks for novel materials.
流体界面处的胶体组装对于自下而上制备新型结构化材料具有巨大潜力。然而，在实现将颗粒可控且可调地组装成各种结构方面仍存在挑战。在此，报道了磁性椭球形Janus颗粒在流体 - 流体界面处的毛细管组装。根据它们的倾斜角度，即颗粒主轴与流体界面形成的角度，这些颗粒会使界面变形并产生毛细管偶极或六极。在毛细管相互作用的驱动下，多个颗粒因此组装成链状、六边形晶格状和环状结构，这些结构可通过施加外部磁场进行主动控制。预测了一个场强相图，其中各种结构以稳定状态存在。由于组装结构的多样性、可控性和可调性，流体界面处的磁性椭球形Janus颗粒因此可作为新型材料的通用构建块。
