基于电流监测法的粗糙表面微通道电渗流实验研究

制作2种 PMMA 微流控芯片,对其微通道内表面参数进行测试。基于电流监测法,设计微流控芯片电渗流检测系统。首先测量光滑微通道电渗流速度,验证了实验的可行性,并可以预测微通道的表面电势;然后对粗糙微通道电渗流进行测量;最后对比分析电场强度、溶液浓度等对光滑和粗糙微通道电渗流的影响。结果表明:(1)不规则粗糙表面微通道电渗流速度随电场强度、溶液浓度的变化规律和光滑表面微通道一致;(2)相对于光滑表面微通道,粗糙表面微通道电渗流速度明显降低;当相对微通道深度为5%时,降低幅度约为23%。(3)随着电场强度或者溶液浓度的增大,粗糙和光滑微通道电渗流速度的差距增大。所用实验方法具有直观、方便和成本低的优点。

Experimental research of electroosmotic flow in rough microchannels based on current-monitoring method

Two kinds of PMMA microfluidic chips were manufactured,and the surface param-eters of the microchannels were tested.A electroosmotic flow (EOF)experimental system with the microfluidic chip was designed based on the current-monitoring method.Firstly,the EOF ve-locity in smooth microchannels was measured,which validated the feasibility of the experimental method.The method can predict the microchannel surface potential.Secondly,the EOF velocity in rough microchannels was measured.Finally,the influence of the electric strength and ionic concentration on the EOF in smooth and rough microchannels was analyzed .The results show that:(1 )The EOF velocity in smooth and rough microchannels is proportional to the electric strength;the EOF velocity decreases with the increase of ionic concentration both in smooth and rough microchannels.(2)The EOF velocity in rough microchannels is significantly decreased. The velocity is decreased by 23%,when the relative roughness is 5%.(3)The gap between the EOF velocities in smooth and rough microchannels increases with the increase of electric strength or solution concentration.The experimental method possesses the advantage of being intuitive, convenient and low cost.