Stationary Electro-osmotic Flow Driven by ac Fields around Insulators

Electric fields are commonly used for manipulating particles and liquids in microfluidic systems. In this work, we report stationary electro-osmotic flow vortices around dielectric micropillars induced by ac electric electrolytes. The characteristics theoretically predicted based on the well-known phenomena of surface conductance concentration polarization a charged object. flows arise from two distinct contributions working together: an oscillating nonuniform zeta potential pillar rectified field ion gradients. We refer to fluid as concentration-polarization electro-osmosis (CPEO). present experimental data support theoretical predictions. magnitude frequency dependence velocity agreement with estimates significantly different predictions standard theory induced-charge electro-osmosis, which has previously been postulated origin objects. addition furthering our understanding influence flows, anticipate that work will also expand use control