Yang Jun, Masliyah J H, Kwok Daniel Y
Nanoscale Technology and Engineering Laboratory, Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta T6G 2G8, Canada.
Langmuir. 2004 May 11;20(10):3863-71. doi: 10.1021/la035243u.
Real surfaces are typically heterogeneous, and microchannels with heterogeneous surfaces are commonly found due to fabrication defects, material impurities, and chemical adsorption from solution. Such surface heterogeneity causes a nonuniform surface potential along the microchannel. Other than surface heterogeneity, one could also pattern the various surface potentials along the microchannels. To understand how such variations affect electrokinetic flow, we proposed a model to describe its behavior in circular microchannels with nonuniform surface potentials. Unlike other models, we considered the continuities of flow rate and electric current simultaneously. These requirements cause a nonuniform electric field distribution and pressure gradient along the channel for both pressure-driven flow (streaming potential) and electric-field-driven flow (electroosmosis). The induced nonuniform pressure and electric field influence the electrokinetic flow in terms of the velocity profile, the flow rate, and the streaming potential.
实际表面通常是不均匀的，由于制造缺陷、材料杂质以及溶液中的化学吸附作用，具有不均匀表面的微通道很常见。这种表面不均匀性会导致沿微通道的表面电位不均匀。除了表面不均匀性外，人们还可以在微通道上对各种表面电位进行图案化处理。为了理解这种变化如何影响电动流动，我们提出了一个模型来描述其在具有非均匀表面电位的圆形微通道中的行为。与其他模型不同，我们同时考虑了流速和电流的连续性。这些要求导致在压力驱动流（流动电势）和电场驱动流（电渗）中沿通道产生不均匀的电场分布和压力梯度。所诱导的不均匀压力和电场在速度分布、流速和流动电势方面影响电动流动。
