TIME-RESOLVED EXPERIMENTAL-STUDY OF SHEAR VISCOSITY IN THE COURSE OF SPINODAL DEMIXING

A large transient surge of shear viscosity is observed in the course of spinodal demixing caused by off-critical quenching of a polymer solution. A characteristic length is derived from light scattering measurements along with a related relaxation time tau(M) whose value agrees with previous independent experiments. Viscosity peak values plotted versus S-tau(M) (where S is the shear rate) lie on a master curve of the type (S-tau(M))-p, where p almost-equal-to 2. This scaling procedure helps bring into focus the mechanism responsible for the novel observation.