  The microchannel corner is a common inherent component of most planar
microfluidic systems and thus its influence on the channel flow is of
significant interest. Application of an alternating current electric field
enables quantification of the non-linear induced-charge electro-osmosis (ICEO)
ejection flow effect by isolating it from linear electro-osmotic background
flow which is present under dc forcing. The hydrodynamic flow in the vicinity
of a sharp channel corner is analyzed using experimental
micro-particle-image-velocimetry (PIV) and numerical simulations for different
buffer concentrations, frequencies and applied voltages. Divergence from the
purely ICEO flow with increasing buffer conductivity is shown to be a result of
increasing electro-thermal effects due to Joule heating.
