A seamlessly integrated microfluidic pressure sensor based on an ionic liquid electrofluidic circuit

A novel pressure sensor with electrical readout based on ionic liquid (IL) electrofluidic circuit is reported in this paper. The pressure measurement is achieved by measuring the electrical property variation of the circuit induced by the pressure inside the microfluidic devices. The sensor integrated microfluidic device is made of polydimethylsiloxane (PDMS), and can be fabricated using the well-developed multilayer soft lithography (MSL) without additional microfabrication processes. Therefore, the pressure sensor is fully disposable, and can be seamlessly integrated into PDMS microfluidic devices. Moreover, an IL electrofluidic Wheatstone bridge is designed to provide the device linear output, great long-term and thermal stability. In this paper, the sensor performance characterization using pressurized gas and liquid flowing in the microfluidic channel have been conducted. The experimental results demonstrate the advantages of the device. The developed pressure sensor has great potentials for the development of next generation sensor-integrated microfluidic systems.