Measurement of Normal Stress Differences in Solutions of Macromolecules

Abstract

THE measurement of normal stress differences generated in the steady laminar shearing motion of solutions of macromolecules has attracted a great deal of attention1. The experimental work has been performed almost exclusively at low shear rates using three well known flow geometries: the concentric cylinder, parallel plate and the cone and plate geometry. The use of these three curvilinear geometries has been described in detail elsewhere and the current position is that determination of the three normal stress differences (usually labelled p11–p22, p22–p33, p33–p11) involves the use of more than one shearing geometry1.