Electrically Driven Rotation and Nonreciprocal Motion of Microparticles in Nematic Liquid Crystals.
Electrically Driven Rotation and Nonreciprocal Motion of Microparticles in Nematic Liquid Crystals.
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DOI：
10.1002/smll.202003352
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发表时间：
2020-09
期刊：
影响因子：
13.3
通讯作者：
N. V. Solodkov;A. Saxena;J. C. Jones
中科院分区：
文献类型：
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作者：
N. V. Solodkov;A. Saxena;J. C. Jones
向列相液晶中微粒子的分散通过拓扑结构和外部刺激的结合为控制微粒子的取向和位置提供了一种新的方法。本文研究了向列型液晶填充的平行板电容器电池中的立方和三角棱柱状微粒子。实验结果与数值模拟结果的比较表明，粒子的最佳取向是由它们的纵横比、它们的容器的相对分离间隙和外加电压决定的。观察到，在允许不受限制的粒子旋转的系统中，粒子的长轴能够与外电场完全对齐。然而，当粒子的旋转受到几何限制时，发现增加电压超过一个临界值会导致粒子的短轴由于锚定断裂而与电场重新对齐。结果表明，在去除电场后，粒子的对称性在它们的动力学中起着关键作用，允许三角形棱镜垂直于外加电场运动，而立方体粒子只有旋转是可能的。
Dispersion of microparticles in nematic liquid crystals offers a novel means for controlling both their orientation and position through the combination of topology and external stimuli. Here, cuboidal and triangular prism shaped microparticles in parallel plate capacitor cells filled with a nematic liquid crystal are studied. Experimental observations are compared with numerical simulations to show that the optimal orientation of the particles is determined by their aspect rations, the relative separation gap of their containers and the applied voltage. It is observed that in systems that allow unrestricted particle rotation, the long axes of the particles are able to fully align themselves with the external electric field. However, when particle rotation is geometrically restricted, it is found that increasing the voltage past a critical value causes the short axis of the particle to realign with the electric field due to anchoring breaking. It is shown that symmetry of the particles then plays a key role in their dynamics following the removal of the electric field, allowing the triangular prisms to travel perpendicular to the applied electric field, whereas only rotation is possible for the cuboidal particles.