High shear microfluidics and its application in rheological measurement

High shear rheology was explored experimentally in microchannels (150×150 m). Two aqueous polymer solutions, polyethylene oxide (viscoelastic fluid) and hydroxyethyl cellulose (viscous fluid) were tested. Bagley correction was applied to remove the end effect. Wall slip was investigated with Mooneys analysis. Shear rates as high as 10⁶ s^–1 were obtained in the pressure-driven microchannel flow, allowing a smooth extension of the low shear rheological data obtained from the conventional rheometers. At high shear rates, polymer degradation was observed for PEO solutions at a critical microchannel wall shear stress of 4.1×10³ Pa. Stresses at the ends of the microchannel also contributed to PEO degradation significantly.