Liquid crystal-enabled electrophoresis and electro-osmosis
Liquid crystal-enabled electrophoresis and electro-osmosis
复制标题
液晶电泳和电渗透
DOI：
10.1142/9789814619264_0012
复制
发表时间：
2017
期刊：
影响因子：
64.8
通讯作者：
O. Lavrentovich
中科院分区：
文献类型：
--
作者：
O. Lavrentovich
本文对各向同性和各向异性（液晶）电解质中的动电效应进行了比较研究。特别强调的是非线性电动与低速增长的平方所施加的电场。这种现象允许人们用交流电场来驱动颗粒和流体的稳定运动。在各向同性电解质中，导致非线性电动力学的电荷的空间分离是通过固体组分（通常是金属）的性质实现的。如果电解质是液晶（LC），则其各向异性特性使得能够在存在取向扭曲的情况下并且在电场的作用下分离电荷。LC各向异性导致胶体颗粒（液晶使能电泳，LCEP）和LC本身（液晶使能电渗，LCEO）的电驱动运动。感生电荷与所施加的场、指向矢梯度、电导率的各向异性和介电常数的各向异性成比例。电场作用于空间分离的电荷，驱动电渗流。如果指向矢变形缺乏镜像对称性，则LC能够使自由粒子电泳和电渗泵送。LCEK的优点是其机理解除了对固体对应物性质的许多限制。例如，LCEP可以传输颗粒，即使这些颗粒被剥夺任何表面电荷;颗粒甚至可以是与LC或气泡不混溶的流体。以类似的方式，LCEO可以驱动OWS，即使没有电极。LC中的离子电流传统上被认为是显示器中不受欢迎的特性，为颗粒和液体的电动力学、微泵送和混合以及芯片实验室分析等多方面的应用提供了广阔的平台。
This work presents a comparative review of electrokinetic effects in isotropic and anisotropic (liquid crystalline) electrolytes. A special emphasis is placed on nonlinear electrokinetics with ow velocities growing as the square of the applied electric field. This phenomenon allows one to drive steady motion of particles and uids with an alternating-current electric field. In isotropic electrolytes, spatial separation of charges that leads to nonlinear electrokinetics is achieved through the properties of the solid component (typically a metal). If the electrolyte is a liquid crystal (LC), its anisotropic properties enable separation of charges in the presence of orientational distortions and under the action of an electric field. LC anisotropy leads to electrically-driven motion of colloidal particles (liquid crystal-enabled electrophoresis, LCEP) and of the LC itself (liquid crystal-enabled electro-osmosis, LCEO). The induced charge is proportional to the applied field, director gradients, anisotropy of conductivity, and anisotropy of permittivity. The electric field acts on the space separated charges to drive the electro-osmotic ows. If the director deformations lack mirror symmetry, the LC enables electrophoresis of free particles and electro-osmotic pumping. The advantage of LCenabled electrokinetics (LCEK) is that its mechanism lifts many restrictions imposed on the properties of the solid counterpart. For example, LCEP can transport particles even if these particles are deprived of any surface charges; the particles can even be a uid immiscible with a LC or a gas bubble. In a similar fashion, LCEO can drive ows even if there are no oating electrodes. Ionic currents in LCs which have been traditionally considered an undesirable feature in displays offer a broad platform for versatile applications in electrokinetics of particles and uids, micropumping and mixing, and lab-on-a-chip analysis…
影响因子：
44.1
作者：
Marchetti, M. C.;Joanny, J. F.;Simha, R. Aditi
通讯作者：
Simha, R. Aditi