Josh R. Gladden, Rachel Crim, Amanda Gamble and Cecille Labuda. Shear wave propagation in worm-like micellar fluids. J. Acoust. Soc. Am. 135, 2218 (2014).
Abstract. In viscous Newtonian fluids, support of shear waves are limited to the viscous boundary layer. Non-Newtonian fluids which have shear modulus, however, support shear waves over much longer distances. The restoring force responsible for the shear wave propagation arises from the entanglement of high aspect ratio macromolecules. We report low frequency (30–60 Hz) shear wave studies of aqueous worm-like micellar fluids composed of cetyltrimethylammonium bromide (CTAB) for the surfactant and sodium salicylate (NaSAL) as the salt over a wide concentration range (20–500 mM CTAB). Shear speeds range from 75 to 700 mm/s over this concentration range at room temperature with evidence of two phase transitions at 200 mM and 375 mM CTAB. Shear stress attenuation and temperature resolved measurements between 20 and 40 C will also be presented.