Rheo-NMR of Wormlike Micelles Formed from Nonionic Pluronic Surfactants

Douglass, Bradley; Colby, Ralph H.; Madsen, Louis A.; Callaghan, Paul T.

doi:10.1021/ma071807f

Cited by 24 publications

(12 citation statements)

References 70 publications

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“…The first direct MRI observation of this type concerned micellar solutions Callaghan 1997a,b, 1999). This was afterwards confirmed by similar tests in Couette cells (Douglass et al 2008), but later, more sophisticated NMR measurements showed that shear-banding fluctuations (Lopez-Gonzalez et al 2006, Al-kaby et al 2018 and exchanges between coexisting phases (Medronho et al 2011) also occur, in keeping with observations with other techniques (Fardin and Lerouge 2012).…”

Section: R Rsupporting

confidence: 57%

Progress in rheology and hydrodynamics allowed by NMR or MRI techniques

Coussot

2020

Exp Fluids

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We review the uses of nuclear magnetic resonance techniques for experiments with fluids. More precisely we focus on the progress of knowledge in complex flows, rheology of complex fluids, flow in porous media, colloid transport, fluid transfers in complex porous systems, which have been allowed by NMR techniques. These achievements took advantage of the versatility of NMR, which makes it possible to carry out more original measurements than the basic well-known density imaging (MRI). One may thus rely on non-destructive, non-invasive, local velocimetry, local rheometry, statistical approaches of molecular displacements or velocity, distribution of adsorbed or suspended colloids, evolution of the liquid distribution in different states, fluid transfers during drying or imbibition, etc.

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Section: R Rsupporting

confidence: 57%

Progress in rheology and hydrodynamics allowed by NMR or MRI techniques

Coussot

2020

Exp Fluids

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“…In these systems shear can induce breakage of the constitutive chains as well as alignment [11][12][13][14][15][16] , which both contribute to the stress relaxation required for strong shear thinning. Breakage and alignment also play important roles in shear-banding hydrogenbonded supramolecular polymers 17 , while shear-banding in dispersions of actin filaments 18 and block-copolymer wormlike micelles 19,20 is caused by alignment and shear-banding in associative polymer networks 21 is caused by breakage. Whether shearbanding is a generic phenomenon for the more common case of entangled polymeric systems is still under debate.…”

Section: Introductionmentioning

confidence: 99%

Shear-banding in entangled xanthan solutions: tunable transition from sharp to broad shear-band interfaces

et al. 2018

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We report on the smooth transition between gradient-banded velocity profiles with a sharp interface and curved velocity profiles, both resulting from strong shear-thinning dispersions of concentrated xanthan (a highly charged poly-saccharide). Pronounced shear-banded flow, where two extended shear-bands are separated by a relatively sharp interface, is observed in a limited range of shear rates, at very low ionic strength and at a high concentration, using heterodyne light scattering to measure spatially resolved velocity profiles. The width of the interface between the coexisting shear-bands broadens to span a sizable fraction of the gap of the shear cell, either by changing the shear rate, by lowering the concentration, or by increasing the ionic strength. The broadening results in a smooth transition to highly curved velocity profiles and is connected to a disappearing flow birefringence. Thus, these experiments show that the classic shear-banding instability can give rise to highly curved velocity profiles, due to the existence of broad interfaces between the bands, with an extent of the order or larger than the cell gap width. This observation may aid to resolve the ongoing dispute concerning shear-banding of highly entangled polymeric systems, suggesting that the curved velocity profiles that have been observed in the past are in fact shear-banded states with an unusually broad interface.

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“…The origins of a declining stress in the stress/shear rate curve are believed to be associated with the formation of shear‐induced structures. The plateau on the flow curve, which is indicative of a ‘shear‐banding’ phenomenon in which two different viscosity states of the same solution can coexist, was found to be a characteristic feature of wormlike micellar nonlinear rheology, a shear‐induced phase transition from isotropic to nematic phase, wall slip and shear stress fluctuations . Stress fluctuations have been found for a variety of micelle systems associated with the growth and destruction of the shear induced in shear‐thickening systems.…”

Section: Rheological Propertiesmentioning

confidence: 97%