Low voltage electroosmotic pump for high density integration into microfabricated fluidic systems

Abstract

A low voltage electroosmotic (eo) pump suitable for high density integration into microfabricated fluidic systems has been developed. The high density integration of the eo pump required a small footprint as well as a specific on-chip design to ventilate the electrolyzed gases emerging at the platinum (Pt) electrodes. For this purpose, a novel liquid¿gas (lg) separator was invented. This lg-separator separated the gas bubbles from the liquid and guided them away from the eo pump. Its operational principle was solely based on the geometry of tapered sidewalls. An eo pump sandwiched by two lg separators (microchannels in the range of 10 lm, footprint of 100 lm 9 15 lm) was experimentally investigated. The lg-separator was able to reliably separate and ventilate an emerging gas flow of 2 pl s-1. The eo pump achieved flow rates of 50 pl s-1 at actuation voltages of 5 V.