Electrokinetic pump having capacitive electrodes

Abstract

An electrokinetic pump achieves high and low flow rates without producing significant gaseous byproducts and without significant evolution of the pump fluid. A first feature of the pump is that the electrodes in the pump are capacitive with a capacitance of at least 10 −4 Farads/cm 2 . A second feature of the pump is that it is configured to maximize the potential across the porous dielectric material. The pump can have either or both features.

What is claimed is: 
     
         1 . An electrokinetic system, comprising:
 an electrokinetic device including a pair of electrodes and a porous dielectric material between the electrodes, the pair of electrodes capable of having a voltage drop therebetween;   a liquid in the elecktrokinetic device between the pair of electrodes;   a power supply; and
 a controller, the controller configured to: 
   (a) apply a positive current from the power supply to the electrodes to charge the capacitance of the electrodes and to move the liquid through the porous dielectric material in a first direction;   (b) reverse the current applied by the power supply to the electrodes prior to reaching a threshold voltage for a Faradaic process in the liquid; and   (c) apply a negative current from the power supply to the electrodes to move the liquid through the porous dielectric material in a second direction that is opposite to the first directions.