We demonstrate a microelongational streaming generated by nonlinear electro-osmosis with high-frequency ac polarization. The phenomenon is attributed to the unique rectification mechanism that coordinates three-dimensional flow interactions between adjacent microvortices in an asymmetric quadrupole electric field. This streaming exhibits a stagnation-point structure with velocity of 300 μm/s at 100 Hz due to Faradaic polarization, but is reversed with slower velocity at 1 kHz by Ohmic charging. The measured extensional rate shows a quadratic dependence on the field in line with nonlinear Smoluchowski scale. The flow can be ready to control fluid transport and manipulate particles in microdevices.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)