Simultaneous microscopic and macroscopic observation of shear-banding for a CTAB/NaSal wormlike micellar solution in large amplitude oscillatory shear

Abstract

The shear-banding and the shear-induced structure (SIS) of CTAB/NaSal wormlike micellar solution in large amplitude oscillatory shear in concentric cylinder flow cell were investigated by the simultaneous macroscopic and microscopic observation. The crossed-Nicols polarizer method was used to detect the distributions of birefringence and orientation angle along the radial direction. The shear-banding was visualized by the distribution of birefringence and generation of SIS was estimated by the change of the stress-optical coefficient. The critical conditions of the shearbanding and SIS in the large amplitude oscillatory shear were plotted on the shear strain - shear rate chart. The SIS condition coincided those the step shear reported previously.