S054025 Effect of pre-shear on shear-hardening of wormlike micelles solutions

Abstract

Influence of pre-shear on the shear-hardening behavior of a wormlike micelles solution in step shear flow is experimentally examined. The peak stress during the shear-hardening decreases with increasing the shear rate of the pre-shear. A component of the contribution of shear- hardening in the shear stress is evaluated by deducting the shear stress of the steady state from shear stress. When integration of the shear stress component of the shear-hardening by shear strain is defined as a shear energy caused by the shear-hardening, the maximum value of it decreases with increasing the shear rate of the pre-shear. By introducing non-dimensional shear rate, which is defined as shear rate in the product of the relaxation time, the maximum shear energy for the shear rate in the first step shear can be plotted on a curve but it depends on the micelles conformation.