Flow-induced structure change of CTAB/NaSal aqueous solution in sinusoidal shear flow

摘要

Flow-induced structure change of a surfactant solution caused by sinusoidal shear flow was investigated. An aqueous solution of CTAB/NaSal is used as a test fluid and it is known that this surfactant makes wormlike micelles and it causes flow-induced structure change in step shear. In this experiment, it is found that the sinusoidal shear strain also causes shear-induced structure change and the appearance condition of critical shear strain and shear rate is almost the same measured by step shear. The maximum shear stress at the first period is very high and it decreases at the following period. The relaxation time of this reducing maximum shear stress was evaluated and it is found that it is decreasing with increasing angular frequency and with increasing the maximum strain.