Yan Ying, Luo Jing, Guo Dan, Wen Shizhu
Tsinghua University, State Key Lab of Tribology, Beijing, P. R. China.
PLoS One. 2015 Feb 20;10(2):e0117456. doi: 10.1371/journal.pone.0117456. eCollection 2015.
Ionic-based dielectrophoretic microchips have attracted significant attention due to their wide-ranging applications in electro kinetic and biological experiments. In this work, a numerical method is used to simulate the dynamic behaviors of ionic droplets in a microchannel under the effect of dielectrophoresis. When a discrete liquid dielectric is encompassed within a continuous fluid dielectric placed in an electric field, an electric force is produced due to the dielectrophoresis effect. If either or both of the fluids are ionic liquids, the magnitude and even the direction of the force will be changed because the net ionic charge induced by an electric field can affect the polarization degree of the dielectrics. However, using a dielectrophoresis model, assuming ideal dielectrics, results in significant errors. To avoid the inaccuracy caused by the model, this work incorporates the electrode kinetic equation and defines a relationship between the polarization charge and the net ionic charge. According to the simulation conditions presented herein, the electric force obtained in this work has an error exceeding 70% of the actual value if the false effect of net ionic charge is not accounted for, which would result in significant issues in the design and optimization of experimental parameters. Therefore, there is a clear motivation for developing a model adapted to ionic liquids to provide precise control for the dielectrophoresis of multi-phase ionic liquids.
基于离子的介电泳微芯片因其在电动和生物实验中的广泛应用而备受关注。在这项工作中，采用一种数值方法来模拟微通道中离子液滴在介电泳作用下的动态行为。当离散的液体电介质被包含在置于电场中的连续流体电介质内时，由于介电泳效应会产生电力。如果其中一种或两种流体是离子液体，由于电场感应的净离子电荷会影响电介质的极化程度，力的大小甚至方向都会改变。然而，使用介电泳模型，假设电介质为理想状态，会导致显著误差。为避免模型导致的不准确，这项工作纳入了电极动力学方程，并定义了极化电荷与净离子电荷之间的关系。根据本文给出的模拟条件，如果不考虑净离子电荷的错误影响，这项工作中获得的电力误差超过实际值的70%，这将在实验参数的设计和优化中导致重大问题。因此，开发一种适用于离子液体的模型以精确控制多相离子液体的介电泳具有明确的动机。
