“Tuliplike” Scattering Patterns in Wormlike Micelles under Shear Flow

Using small angle light scattering we report on the formation of a string phase in a semidilute solution of wormlike micelles (0.03M CTAB/0.24M NaSal) under simple shear flow. The string phase appears as a bright narrow streak in the scattering pattern normal to the flow direction. We also study the relaxation behavior after cessation of flow, and using the Brochard–de Gennes model we are able to estimate the stress relaxation time ${\tau }_s$ and diffusion coefficient $D_c$ of the dominant relaxation mode.