Determination of the complex shear modulus of polymer solutions with piezoelectric resonators

Abstract

The new procedure, which was worked out for the determination of complex shear moduli of polymer solutions, comprises an experimental setup working with impedance measurements at liquid covered quartz crystals (network analysis in the MHz range) and a calibration of these sensors concerning their surface roughness and an additional damping from the coupling of shear and compressional waves. As an example the frequency dispersion of the viscosity and shear modulus of aqueous poly(ethylene oxide) and dextran solutions is determined. The steady state value of the viscosity, which depending on concentration (0.1–40 wt.%) lies between 1 and 20 mPa s decreases by about 50% at 90 MHz.