Superposition rheology of shear-banding wormlike micelles

Abstract

Wormlike micelle solutions are submitted to small-amplitude oscillatory shear superimposed to steady shear in the shear banding regime. By imposing a shear oscillation, the interface between high- and low-shear regions oscillates in time. A two-fluid semi-phenomenological model is proposed for superposition rheology in the shear banding regime, which allows us to extract a characteristic velocity for the interface dynamics from experiments involving only a standard rheometer. Estimates of the stress diffusion coefficient $\mathcal{D}$ can also be inferred from such superposition experiments. The validity of our model is confirmed by directly recording the interface displacement using ultrasonic velocimetry.

24 pages, 13 figures

References in corpus (5)

• Flow phase diagrams for concentration-coupled shear banding
• Spatio-temporal dynamics of wormlike micelles under shear
• Spatio-temporal oscillations and rheochaos in a simple model of shear banding
• Interface instability in shear banding flow
• Early stages of the shear banding instability in wormlike micelles

Cited by in corpus (2)

• Recent experimental probes of shear banding
• Shear-induced transitions and instabilities in surfactant wormlike micelles