Observation of shear banding in worm-like micelles by NMR velocity imaging
- 20 December 1996
- journal article
- Published by IOP Publishing in Europhysics Letters
- Vol. 36 (9), 719-724
- https://doi.org/10.1209/epl/i1996-00293-9
Abstract
We report an observation of shear-banding, under Couette flow, of the worm-like surfactant system cetyl pyridinium chloride/sodium salicylate (respective concentrations of 100 mM and 60 mM in pure water). The method, based on NMR velocity imaging, allows the direct measurement of velocity, and consequent calculation of shear rate, at a spatial resolution of around 10 μm, sufficient to resolve apparent slip at the inner wall from shear banding within the bulk of the fluid. Above a critical shear rate (around 1 s−1) a high shear rate band is observed in the annulus between concentric rotating cylinders, the width of the band being of order 30 μm with a corresponding shear rate of order 500 s−1. The precise location of the band is sensitive to boundary conditions at the inner wall and is shown to be susceptible to significant broadening.Keywords
This publication has 12 references indexed in Scilit:
- Nonmonotonic Constitutive Laws and the Formation of Shear-Banded FlowsJournal de Physique II, 1996
- A Study of the “Spurt Effect" in Wormlike Micelles Using Nuclear Magnetic Resonance MicroscopyJournal de Physique II, 1996
- Rheo-Optical Study of Worm-like Micelles Undergoing a Shear Banding FlowEurophysics Letters, 1995
- Flow birefringence experiments showing a shear-banding structure in a CTAB solutionColloid and Polymer Science, 1995
- Nuclear magnetic resonance imaging of flow for a shear-thinning polymer in cylindrical Couette geometryJournal of Rheology, 1994
- Nonlinear rheology of wormlike micellesPhysical Review Letters, 1993
- The Rheology of Entangled Polymers at Very High Shear RatesEurophysics Letters, 1993
- Viscoelastic surfactant solutions: model systems for rheological researchMolecular Physics, 1991
- Study of shear thinning in high polymer solution using dynamic NMR microscopyMacromolecules, 1991
- A molecular approach to the spurt effect in polymer melt flowJournal of Polymer Science Part B: Polymer Physics, 1986