Electroosmotic pump


An electroosmotic pump, or EO pump, is used for generating flow or pressure by use of an electric field. One application of this is removing liquid flooding water from channels and gas diffusion layers and direct hydration of the proton exchange membrane in the membrane electrode assembly of the proton exchange membrane fuel cells.

Principle

Electroosmotic pumps are fabricated from silica nanospheres or hydrophilic porous glass, the pumping mechanism is generated by an external electric field applied on an electric double layer, generates high pressures and high flow rates. EO pumps are compact, have no moving parts, and scale favorably with fuel cell design. The EO pump might drop the parasitic load of water management in fuel cells from 20% to 0.5% of the fuel cell power.

Types

Cascaded electroosmotic pumps

High pressures or high flow rates are obtained by positioning several regular electroosmotic pumps in series or parallel respectively.

Porous electroosmotic pump

Porous pumping is created by the use of sintered glass.

Planar shallow electroosmotic pump

Planar shallow electroosmotic pumps are made of parallel shallow microchannels.

Electroosmotic micropumps

Electroosmotic effects can also be induced without external fields in order to power micron-scale motion. Bimetallic gold/silver patches have been shown to generate local fluid pumping by this mechanism when hydrogen peroxide is added to the solution. A related motion can be induced by silver phosphate particles, which can be tailored to generate reversible firework behavior among other properties.