Dynamic shear viscosity measurements in aqueous sodium deoxycholate solutions

Abstract

The real component of shear impedance, R_L, was measured in concentrated aqueous solutions of sodium deoxycholate, by means of different experimental techniques, in the frequency range 30KHz – 830MHz, at temperatures from 20°to 40°C. The results obtained give direct confirmation on the existence of viscoelastic effects in such a system; they allow, also, to evaluate an upper limit for the dynamic shear viscosity values. From these data it is evident that shear viscosity relaxes well below the usual frequency range of longitudinal ultrasonic experiments. As a consequence, the previously observed large longitudinal ultrasonic absorption appear to be due mainly to volume viscosity contributions.