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电渗流(EOF)广泛应用于微流控芯片中的流体传输与混合.针对具有一定滑移长度的疏水表面微通道,建立了描述EOF的控制方程,基于有限元分析方法对微通道EOF进行了数值模拟,研究了微通道高度、电场强度和溶液浓度等对EOF的影响.结果表明,疏水表面和亲水表面微通道EOF的瞬态过程相似,稳态时间尺度在ms量级,大小与微通道高度的平方成正比;EOF速度大小与电场强度成正比,与微通道高度无关;由于边界滑移的存在,疏水表面比亲水表面EOF速度明显增大,且随着溶液浓度的增大,EOF速度增大相对要大的多.该结论对于具有一定滑移长度的疏水表面微通道内EOF的精确操控具有一定的参考意义.
Electroosmotic flow (EOF) is widely used in the transmission and mixing of fluids in microfluidic chips.For the hydrophobic surface microchannels with a certain sliding length, a control equation describing EOF is established, and based on the finite element analysis method, the micro channel EOF Numerical simulations were carried out to investigate the influence of microchannel height, electric field strength and solution concentration on EOF.The results show that the transient processes of hydrophobic surface and hydrophilic surface microchannel EOF are similar, and the steady-state time scale is on the order of magnitude, The EOF velocity is proportional to the electric field intensity and has no relation with the height of the microchannel. Due to the boundary slip, the EOF velocity of the hydrophobic surface is obviously higher than that of the hydrophilic surface. With the increase of solution concentration, The increase of EOF is much larger than that of EOF.The conclusion is of some reference to the precise control of EOF in hydrophobic surface microchannels with a certain sliding length.