Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, PO Box 5190, Kent, Ohio 44242, USA.
Nat Commun. 2014 Sep 25;5:5033. doi: 10.1038/ncomms6033.
Electrically controlled dynamics of fluids and particles at microscales is a fascinating area of research with applications ranging from microfluidics and sensing to sorting of biomolecules. The driving mechanisms are electric forces acting on spatially separated charges in an isotropic medium such as water. Here, we demonstrate that anisotropic conductivity of liquid crystals enables new mechanism of highly efficient electro-osmosis rooted in space charging of regions with distorted orientation. The electric field acts on these distortion-separated charges to induce liquid crystal-enabled electro-osmosis. Their velocities grow with the square of the field, which allows one to use an alternating current field to drive steady flows and to avoid electrode damage. Ionic currents in liquid crystals that have been traditionally considered as an undesirable feature in displays, offer a broad platform for versatile applications such as liquid crystal-enabled electrokinetics, micropumping and mixing.
微尺度下流体和颗粒的电控动力学是一个引人入胜的研究领域，其应用范围从微流控和传感到生物分子的分类。驱动机制是各向同性介质（如水）中空间分离电荷上的电场力。在这里，我们证明了液晶的各向异性导电性能够实现一种新的高效电渗透机制，其根源在于具有扭曲取向的区域的空间电荷。电场作用于这些变形分离电荷，以诱导液晶电渗透。它们的速度随电场的平方增长，这使得人们可以使用交流电场来驱动稳定的流动，并避免电极损坏。在传统上被认为是显示器中不良特征的液晶中的离子电流，为各种应用提供了一个广泛的平台，如液晶驱动的动电学、微泵和混合。
