Electrofluidic Circuit-Based Microfluidic Viscometer for Analysis of Newtonian and Non-Newtonian Liquids under Different Temperatures

This paper reports a microfluidic viscometer with an integrated pressure sensor based on electrofluidic circuits, which are electrical circuits constructed by ionic liquid-filled microfluidic channels. The electrofluidic circuit provides a pressure-sensing scheme with great long-term and thermal stability. The viscosity of the tested fluidic sample is estimated by its flow resistance, which is a function of pressure drop, flow rate, and the geometry of the microfluidic channel. The viscometer can be exploited to measure viscosity of either Newtonian or non-Newtonian power-law fluid under various shear rates (3–500 1/s) and temperatures (4–70 °C) with small sample volume (less than 400 μL). The developed sensor-integrated microfluidic viscometer is made of poly(dimethylsiloxane) (PDMS) with transparent electrofluidic circuit, which makes it feasible to simultaneously image samples under tests. In addition, the entire device is disposable to prevent cross-contamination between samples, which is desired for ...