Osmotically driven flows in microchannels separated by a semipermeable membrane
Kåre Hartvig Jensen
Fluid•DTU
Department of Micro- and Nanotechnology
Abstract:
Osmotically driven flows in microchannels are studied experimentally and theoretically. The propagation of a front of sugar solutions has been measured using dye and particle tracking in 200 mu wide and 50, 100 and 200 mu high polymer-based microchannels. Each of these microchannels was separated by a semipermeable membrane from a reservoir containing pure water. We find that the sugar front travels with constant speed, and that this speed is proportional to the concentration of the sugar solution and inversely proportional to the depth of the channel. The theoretical predictions agree well with the measurements.
Our motivation for studying osmotically driven flows are, that these are believed to be responsible for the translocation of sugar in plants. Also, we suggest that our channel design can be used as the driving mechanism in integrated micropumps with no movable parts.