Electrothermal ac electro-osmosis

Gagnon, Zachary R.; Chang, Hsueh-Chia
January 2009
Applied Physics Letters;1/12/2009, Vol. 94 Issue 2, pN.PAG
Academic Journal
Two ac polarization mechanisms, charge accumulation due to electrode double layer charging and bulk permittivity/conductivity gradients generated by Joule heating, are combined in the double layer by introducing zwitterions to produce a new ac electrokinetic pump with the largest velocity (>1 mm/s) and flow penetration depth (100 μm) reported for low-conductivity fluids. The large fluid velocity is due to a quartic scaling with respect to voltage, as is true of electrothermal flow, but exhibits a clear maximum at a frequency corresponding to the electrode double layer inverse RC time.


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