Title:           Induced-Charge Electro-osmosis

Speaker:         Martin Z. Bazant
                 Associate Professor of Applied Mathematics
                 Institute of Soldier Nanotechnologies
		 MIT

Abstract: 

"Induced-charge electro-osmosis" (ICEO) refers to the nonlinear slip
of a liquid electrolyte at a polarizable (metal or dielectric) surface
when an electric field acts on its own induced double-layer
charge. "Induced-charge electrophoresis" (ICEP) refers to motion of a
polarizable particle due to ICEO flow with broken symmetry.  In this
talk, we present the basic theory of ICEO and ICEP, as well as
(subsequent) experiments demonstrating ICEO flows in microfluidic
devices and ICEP motion in colloids.  Current engineering applications
in our lab include three-dimensional electrokinetic pumps, which
outperform planar AC electro-osmotic pumps by an order of magnitude
(e.g. mm/sec flow at 1 Volt kHz AC) and thus enable portable
lab-on-a-chip technology. Such devices typically place "large"
voltages (>> kT/e) across the double layer, so we are extending the
theory of ICEO to account for steric and viscoelectric effects at
highly charged surfaces. This is a first step toward understanding how
solution chemistry affects nonlinear electrokinetics.
                                                                              
For more information, see http://math.mit.edu/~bazant/ICEO.