FINE-TUNING ELECTRICAL FLOW RATE SENSING IN DEFORMABLE CHANNELS
Pengfei Niu, Brian J. Nablo, Kiran Bhadriraju, Darwin R. Reyes-Hernandez
Here we present conclusive proof that when using electrical impedance to measure volumetric flow rate in polydimethylsiloxane (PDMS) microchannels a considerable fraction of the change in impedance, due to change in flow rate, is caused by the variation in bulk solution resistance rather than the disruption of the Helmholtz double layer. The variation in solution resistance is caused, in part, by the channel deformation under pressure. Placing electrodes near the microchannel inlet produces higher sensitivity due to greater channel deformation than those at the outlet. This finding is of paramount importance for the future design of impedance- based flow sensors.
Proceedings of Micro Total Analysis Systems 2016
October 9-13, 2016
The 20th International Conference on Miniaturized Systems for Chemistry and Life Sciences