Department of Mechanical Engineering, Postech, Pohang 790-784, Republic of Korea.
J Colloid Interface Sci. 2011 May 15;357(2):521-6. doi: 10.1016/j.jcis.2011.01.107.
A two-fluid electroosmotic flow in a microchannel is studied by considering full hydrodynamic and electrostatic interactions on the interface. Jumps in electrical potential and in charge density across the interface, in particular, are found to create counterintuitive flow behavior through the electrostatic interaction of the interface with the external field imposed. The interfacial electrostatic effects are shown to induce flow reversal within physically reasonable parametric ranges. It is also shown that the electrostatic properties of the interface must be carefully considered in electroosmotic pumping lest the nonconducting fluid should stay stationary or flow in an unintended direction. A formula for quantitative control of electroosmotic pumping is provided.
通过考虑微通道中全流体动力学和静电相互作用，研究了两流体电渗透流。特别是发现，通过界面与外部施加电场的静电相互作用，跨界面的电势和电荷密度跃变会产生违反直觉的流动行为。界面静电效应表明，在物理上合理的参数范围内会引起流动反转。还表明，在电渗透泵送中必须仔细考虑界面的静电特性，以免不导电的流体保持静止或流向意想不到的方向。提供了一种用于定量控制电渗透泵送的公式。
