OSCILLATORY SHEAR-INDUCED ANISOTROPIC DOMAIN GROWTH AND RELATED RHEOLOGICAL PROPERTIES OF BINARY-MIXTURES

Numerical simulation based on the modified time-dependent Ginzburg-Lan dau (TDGL) model has been performed on the domain growth and related r heological properties of binary mixtures under oscillatory shear. The simulation results reveal that the domain growth is anisotropic and de pends on the quench depth. It is found that, in the deep quench case, the disclike domain with the normal parallel to the velocity gradient direction is observed, while in the shallow quench case, the rodlike d omain with rod axis aligned along the flow direction is observed. The scattering functions for different light incident directions are calcu lated and suggest that the undulated rodlike morphology is formed in t he shallow quench case. This undulated rodlike morphology shows the an omalous rheological response. A plausible interpretation for the anoma lous rheological property is proposed based on the deformation of the undulated rodlike morphology under oscillatory shear. (C) 1998 America n Institute of Physics.