Ionic Liquid Electrofluidic Pressure Sensors with Embedded Analog and Digital Circuitry Functions

This paper reports a novel method to integrate pressure sensors with analog and digital circuitry functions into microfluidic systems based on ionic liquid (IL) electrofluidic circuits. The developed pressure sensors possess electrical readout and can be seamlessly embedded into the microfluidic systems. The entire device is fabricated using an elastomeric material, polydimethylsiloxane (PDMS), and the electrofluidic circuits are achieved by IL filled fluidic networks. The analog functions are constructed based on Wheatstone bridge circuits with output of the additive or subtractive results of the pressurized variable resistors. The digital functions are built using the electrofluidic circuits with on-off logic gates, of which the states are regulated by the applied pressures. The experimental results demonstrate the designed functions are successfully achieved, making it possible to develop an integrated microfluidic system with capabilities of precise pressure monitoring and further feedback control.