Viscosity measurement using hydrodynamic divergencing chamber and digital counting in microfluidic channels

This paper reports an efficient method to measure fluid viscosity in microchannels using hydrodynamic diverging chamber and digital counting. A proposed microfluidic viscometer is designed to have two inlets for sample as well as reference fluids, and a divergencing channel with 89 channels for digital counting. DI water and SDS solutions are used as a reference fluid and a sample fluid, respectively. The viscosities measured by the proposed microfluidic viscometer are compared with the ones measured by a commercially available viscometer (HAAKE MARS). The averaged deviation for four different viscosities measured by both viscometers is only about 2.5 %. Additionally, the microfluidic viscometer gives more consistent value, especially in low shear rate regime.