1125 CTAB/NaSal 水溶液の定常平面伸張流動特性の解明

Abstract

Rhelogical properties in steady planar elongational flow of CTAB/NaSal aqueous solution, which forms wormlike micelles and shows viscoelastic property, were investigated. 4-roll mill flow cell was used to create steady planar elongational flow. The planar elongational stress was measured by using a flow-birefringence technique which is based on the stress-optic rule. In addition, the planar elongation rate was accurately measured by the motion analysis of tracer particles. The planar elongational viscosity was evaluated from both results and it showed the elongational thinning as the same of the shear thinning. The planar elongational viscosity, which was measured by using 4-roll mill flow cell, was compared with one, which was measured by using squeeze flow cell, and they showed good agreement. Trouton ratio was kept 4 in both Newtonian region and elongational thinning region. The flow instability was observed in 4-roll mill flow cell at a certain planar elongation rate that was lower than the case of shear flow instability