Confinement of surface spinners in liquid metamaterials
Confinement of surface spinners in liquid metamaterials
复制标题
液体超材料中表面旋转器的限制
DOI：
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发表时间：
2019
影响因子：
11.1
通讯作者：
M. Shats
中科院分区：
文献类型：
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作者：
Jean;H. Xia;N. Francois;H. Punzmann;G. Falkovich;M. Shats
控制和分离流体层中单个活性颗粒的能力是生物学和工程环境中的一个挑战，也是受控自组装的一个基本问题。在这里，我们将旋转器放置在类似于光学晶格的波浪驱动的漩涡矩阵中。研究结果提供了一种在由波动产生的流中操纵自旋粒子的方法。旋转器可以被限制在稳定的轨道上，被困在没有固体边界的液体超材料细胞内，或者从细胞中释放出来，可以用来在涡流晶格内携带生物或化学制剂。我们证明了旋转粒子在液气界面可以有效地操纵使用光学晶格的表面波模拟。两个正交驻波产生反向旋转的半波长单元胞，即液体界面超材料的表面流动，其几何形状由波相移控制。在这里，我们证明了通过在这种超材料中放置主动磁性旋转器，可以制造出一种强大的工具，可以操纵和自组装旋转器，将它们变成能够在自主超材料单元细胞之间传输物质和信息的载体。我们讨论了作用在非均匀流携带的旋转体上的力，并展示了这些力是如何将旋转体限制在波浪驱动流的同符号涡胞内的轨道上的。反转旋转，我们将旋转器移动到相邻的单元格中。通过改变旋转频率或波幅，可以精确地控制旋转轨道。单个胞内的多个自旋器自组织成稳定的图案，例如三角形或正方形，绕胞中心旋转。具有不同频率的自旋子也可以被限制，使频率较高的自旋子占据内轨道，频率较低的自旋子在外轨道上运行，两个自旋子的轨道运动是同步的。
Significance The ability to control and separate individual active particles in fluid layers is a challenge in biological and engineering contexts as well as a basic problem of controlled self-assembly. Here we place spinners in a wave-driven matrix of vortices, akin to optical lattices. The results offer a method of manipulating spinning particles within a wave-produced flow. Spinners can be confined on stable orbits, trapped inside, or released from the liquid metamaterial cells without solid boundaries and can be used to carry biological or chemical agents within the vortex lattice. We show that rotating particles at the liquid–gas interface can be efficiently manipulated using the surface-wave analogue of optical lattices. Two orthogonal standing waves generate surface flows of counter-rotating half-wavelength unit cells, the liquid interface metamaterial, whose geometry is controlled by the wave phase shift. Here we demonstrate that by placing active magnetic spinners inside such metamaterials, one makes a powerful tool which allows manipulation and self-assembly of spinners, turning them into vehicles capable of transporting matter and information between autonomous metamaterial unit cells. We discuss forces acting on a spinner carried by a nonuniform flow and show how the forces confine spinners to orbit inside the same-sign vortex cells of the wave-driven flow. Reversing the spin, we move the spinner into an adjacent cell. By changing the spinning frequency or the wave amplitude, one can precisely control the spinner orbit. Multiple spinners within a unit cell self-organize into stable patterns, e.g., triangles or squares, orbiting around the center of the cell. Spinners having different frequencies can also be confined, such that the higher-frequency spinner occupies the inner orbit and the lower-frequency one circles on the outer orbit, while the orbital motions of both spinners are synchronized.