Surface-sensitive particle selection by driving particles in a nematic solvent
Surface-sensitive particle selection by driving particles in a nematic solvent
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DOI：
10.1088/0953-8984/18/15/l05
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发表时间：
2006-04-19
影响因子：
2.7
通讯作者：
Tanaka, Hajime
中科院分区：
文献类型：
--
作者：
Araki, Takeaki;Tanaka, Hajime
电泳和沉淀（或超离心）是分离颗粒、蛋白质和DNA的有力手段，利用颗粒电荷、质量和大小的差异。胶体和蛋白质的表面特性与其物理、化学和生物功能密切相关。因此，根据其表面特性选择粒子是非常可取的。用复杂液体代替水这样的简单液体的可能性可能为颗粒分离提供一种新的途径。本文报道了一种以向列液晶为溶剂的表面敏感粒子选择新原理。当我们将粒子浸入向列液晶中时，如果粒子表面与液晶取向之间存在足够强的耦合（即所谓的表面锚定效应），粒子周围就会形成拓扑缺陷。然后这些缺陷强烈地影响粒子的运动。本文采用一种新颖的数值模拟方法，将弹性耦合和线虫流体动力耦合有机地结合起来。我们发现，在取向向列液晶中，表面锚定特性改变了粒子的运动方向和速度。这一原理可用于根据表面性质来分离颗粒。
Electrophoresis and sedimentation (or ultracentrifugation) are powerful means for separating particles, proteins, and DNA, exploiting the difference in particle charge, mass, and size. Surface properties of colloids and proteins are closely related to their physical, chemical, and biological functions. Thus, the selection of particles in terms of their surface properties is highly desirable. The possibility of replacing a simple liquid like water by a complex liquid may provide a novel route to particle separation. Here we report a new principle of surface-sensitive particle selection by using nematic liquid crystal as a solvent. When we immerse a particle in nematic liquid crystal, topological defects are formed around a particle if there is a strong enough coupling between the particle surface and liquid crystal orientation (so-called surface anchoring effects). Then these defects strongly influence the motion of particles. Here we study this problem by using a novel numerical simulation method which incorporates elastic and nematohydrodynamic couplings properly. We find that the surface anchoring properties change both direction and speed of motion of a particle driven in an oriented nematic liquid crystal. This principle may be used for separating particles in terms of their surface properties.