MACROSCOPIC RESPONSE OF WORMLIKE MICELLES TO ELONGATIONAL FLOW

Opposed nozzle flow is used to measure the elongational properties of wormlike micelles. Well-characterized semidilute micellar solutions of CPCl/Sal in concentrated brine are used, By varying temperature and c oncentration, the viscoelastic properties (tau(R), G(0)) of the equili brium solutions can be controlled and the influence of viscoelasticity on elongational viscosity probed. Results indicate three regimes of s teady elongational behavior: a constant viscosity at low elongational rates, an increase to a maximum viscosity, and then a subsequent drop in viscosity. Scaling of the macroscopic elongational properties with linear viscoelastic parameters and similarities between these solution s and entangled polymer solutions indicate that semidilute CPCl/Sal so lutions do not exhibit significant changes in micellar structure and m ay provide model systems for studying the influence of complex flow fi elds on entangled polymer solutions.