An Ohmic model for electrokinetic flows of binary asymmetric electrolytes

作者：Persat Alexandre^*; Santiago Juan G^*

来源：Current Opinion in Colloid & Interface Science, 2016, 24: 52-63.

DOI：10.1016/j.cocis.2016.06.001

• Electroosmotic flow
• AC electrokinetics
• Induced-charge electroosmosis
• Electrokinetic instabilities
• Leaky dielectric model
• Ohmic model

The transport of electrolytes in electric fields is a ubiquitous phenomenon commonly harnessed in microfluidics. A classic leaky dielectric model for flow generated by electric fields accurately predicts electrohydrodynamic transport phenomenon but is valid for millimeter-scale and larger flows and at relatively low ionic strength. Here, we derive and use a modified version of this model to sub-millimeter scales more relevant to microfluidics, where diffusive transport of charged species becomes non-negligible. We formulate a general equation set, the modified Ohmic model, applicable to the transport of binary, asymmetric electrolytes. We leverage this model to describe a variety of microfluidic electrokinetic systems, including DC electroosmosis, alternating current electrokinetics (ACEK) and induced-charge electroosmosis (ICED), thus highlighting some unifying principles of these flows.

• 出版日期2016-8