Calculation of ac Electric Field Effects on the Average Height of a Charged Colloid: Effects of Electrophoretic and Brownian Motions
Calculation of ac Electric Field Effects on the Average Height of a Charged Colloid: Effects of Electrophoretic and Brownian Motions
复制标题
计算交流电场对带电胶体平均高度的影响：电泳和布朗运动的影响
作者：
J. Fagan;A. Sides;D. Prieve
数值求解了在交变电场、布朗运动和DLVO力作用下，平面壁附近带电胶体粒子随时间变化的概率密度。这是第一个在迁移率梯度中的受驱动粒子的时间依赖的概率分布解。通过数值求解一维完全对流扩散方程，忽略惯性，研究了电泳粒子运动对在铟锡氧化物表面上方给定高度发现单个6 μm直径聚苯乙烯粒子的概率分布的影响。在一个完整的电场周期内，应用交流电场单调增加平均颗粒高度;最强的增加是在低频率和大电场强度。这些结果与在高电压下氢氧化钾溶液中观察到的行为一致，但没有捕捉到在低电压下平均高度的降低。计算…
Numerical solutions are presented for the time-dependent probability density of a charged colloidal particle near a planar wall, subjected to an alternating electric field, Brownian motion, and DLVO forces. These are the first time-dependent probability distribution solutions for a driven particle in a mobility gradient. The effects of electrophoretic particle motion on the probability distribution for finding a single, 6 μm diameter, polystyrene particle at a given height above an indium−tin oxide surface were studied via numerical solution of the complete convective−diffusion equation, ignoring inertia, in one dimension. Application of an ac electric field monotonically increased the average particle height over a complete cycle of the electric field; the strongest increase was at low frequency and large electric field strengths. These results agreed with observed behavior in potassium hydroxide solutions at high voltages but did not capture the depression of the average height at low voltages. The calc...