Building Electronic Circuits Using Liquids: Ionic Liquid Electrofluidic Circuit Microfluidic Pressure Sensors

摘要

This article introduces a microfluidic pressure sensor based on electrofluidic circuits constructed by ionic liquid (IL)-filled microfluidic channels. The developed pressure sensor can be seamlessly fabricated into polydimethylsiloxane (PDMS) microfluidic systems using the well-developed multilayer soft lithography (MSL) technique without additional assembly or sophisticated cleanroom microfabrication processes. As a result, the device can be easily scaled up and is fully disposable. The pressure sensing is achieved by measuring the pressure-induced electrical- resistance variation of the constructed electrofluidic resistor. In addition, an electrofluidic Wheatstone bridge circuit is designed for accurate and stable resistance measurements. The pressure sensor is characterized using pressurized nitrogen gas and the experimental results demonstrate the great long-term stability, temperature stability, and linear characteristics of the developed pressure sensing scheme. Consequently, the integrated microfluidic pressure sensor developed in this paper is promising for better monitoring and for characterizing the flow conditions and liquid properties inside the PDMS microfluidic systems in an easier manner for various applications.