Characterization of pneumatically activated microvalves by measuring electrical conductance

Accurate determination of the mechanical response of pneumatic activated microvalves is important for the optimization of a number of microfluidic elements. In the case of multi-layers PDMS devices, pneumatic activated valves are used in combination for pumping, mixing and other functionalities. In such devices, the mechanical response of a valve depends on the PDMS toughness, the membrane thickness as well as the detail of the channel configuration and the pressure applied in both flow and control channels. We describe characterization technique of a pneumatic activated valve based on conductance measurements of electrolytes in the microfluidic channel. We also show that the well calibrated microvalves can be used for the development of more complex functionalities such as high precision dose control of chemical solutions.