Electroosmotically induced hydraulic pumping with integrated electrodes onmicrofluidic devices

Electroosmotic manipulation of fluids was demonstrated using thin metal ele ctrodes integrated within microfluidic channels at the substrate and cover plate interface. Devices were fabricated by photolithographically patternin g electrodes on glass cover plates that were then bonded to polymeric subst rates into which the channels were cast. Polymeric substrates were used to provide a permeable membrane for the transport and removal of gaseous elect rolysis products generated at the electrodes. Electroosmotic flow between i nterdigitated electrodes was demonstrated and provided electric field-free pumping of fluids in sections of the channel outside of the electrode pairs . The resultant pumping velocities were shown to be dependent on the applie d voltage, not on the applied field strength, and independent of the length of the electroosmotically pumped region.