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 ${\mathrm{\tau }}_{\mathit{M}}$ whose value agrees with previous independent experiments. Viscosity peak values plotted versus S${\mathrm{\tau }}_{\mathit{M}}$ (where S is the shear rate) lie on a master curve of the type (S${\mathrm{\tau }}_{\mathit{M}}$ ${)}^{\mathrm{-}\mathit{p}}$, where p≊2. This scaling procedure helps bring into focus the mechanism responsible for the novel observation.