Ubiquity of domain patterns in sheared viscoelastic fluids

Hobbie, Erik K.; Lin‐Gibson, Sheng; Wang, Haonan; Pathak, Jai A.; Kim, H W.

doi:10.1103/physreve.69.061503

Cited by 23 publications

(16 citation statements)

References 19 publications

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“…The textures can be interpreted as domains of a new phase induced by the shear flow and suggest that, contrary to regime B, the banded structure in regimes D and E is related to a shear-induced phase separation (for example between an isotropic and a nematic phase). Similar domain patterns have been seen in other multiphase flows where they were attributed to a viscoelastic asymmetry between the two phases [5]. In wormlike micelle solutions, a shear-induced phase transition is observed only for very concentrated micellar solutions, close to an equilibrium phase transition [7].…”

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confidence: 55%

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Multiple Shear-Banding Transitions in a Supramolecular Polymer Solution

Gucht

Lemmers²,

Knoben³

et al. 2006

Phys. Rev. Lett.

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We report on the nonlinear rheology of a reversible supramolecular polymer based on hydrogen bonding. The coupling between the flow-induced chain alignment and breakage and recombination of bonds between monomers leads to a very unusual flow behavior. Measured velocity profiles indicate three different shear-banding regimes upon increasing shear rate, each with different characteristics. While the first of these regimes has features of a mechanical instability, the second shear-banding regime is related to a shear-induced phase separation and the appearance of birefringent textures. The shear-induced phase itself becomes unstable at very high shear rates, giving rise to a third banding regime. DOI: 10.1103/PhysRevLett.97.108301 PACS numbers: 83.60.Rs, 47.50.ÿd, 83.60.Wc, 83.80.Rs Coupling between fluid microstucture and flow yields a rich scala of non-Newtonian behavior in complex fluids. Many complex fluids display flow instabilities or flowinduced phase transitions above a critical shear rate or stress. Solutions of wormlike micelles, for example, undergo a shear-banding instability in which the fluid separates in the gradient direction into coexisting regions (bands) supporting different shear rates (''gradient banding'') [1,2]. Rod-like colloids, on the other hand, display ''vorticity banding,'' in which the different shear bands are separated in the vorticity direction [3]. Several other systems, such as attractive emulsions or carbon nanotube suspensions, show an elastic instability that leads to the formation of shear-induced aggregates aligned in the vorticity direction [4,5].Several aspects of these instabilities can be reproduced by phenomenological models, see e.g. [6]. Shear banding in the gradient direction, for example, can be related to a nonmonotonic constitutive equation relating the shear stress and the shear rate _ . When a shear rate is applied in the region where decreases with _ , an initially homogeneous flow becomes mechanically unstable. In the simplest scenario, the system then separates into a weakly sheared band that flows at _ 1 and a highly sheared band that flows at _ 2 [1]. Increasing the overall shear rate within the unstable region leads to an increase of the width of the high shear band, while the stress remains constant. The microscopic origin of the shear-banding instability varies for different systems. For wormlike micelles, two alternative mechanisms for shear banding have been proposed. Cates and coworkers predicted a nonmonotonic constitutive equation leading to a shear-banding instability, based on the Doi and Edwards reptation model for polymers [1]. This purely mechanical instability is responsible for shear banding in semidilute solutions of wormlike micelles, far from an equilibrium phase transition [2]. In more concentrated systems, on the other hand, the appearance of a banded flow is related to a first-order phase transition induced by the flow, such as an isotropic-to-nematic transition [6,7]. In this case, the two shear bands correspond to two structurally ...

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confidence: 55%

“…Rod-like colloids, on the other hand, display ''vorticity banding,'' in which the different shear bands are separated in the vorticity direction [3]. Several other systems, such as attractive emulsions or carbon nanotube suspensions, show an elastic instability that leads to the formation of shear-induced aggregates aligned in the vorticity direction [4,5].…”

mentioning

confidence: 99%

Multiple Shear-Banding Transitions in a Supramolecular Polymer Solution

Gucht

Lemmers²,

Knoben³

et al. 2006

Phys. Rev. Lett.

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“…Similar observations of floc formation have been reported for different complex fluids with attractive interactions, such as carbon nanotube suspensions29 and thixotropic clay gels 30. Osuji and Weitz observed that a similar alignment of highly anisotropic flocs in the vorticity direction for a carbon black colloidal suspension also corresponded to the onset of negative N 1 and was an indication of shear thickening 31.…”

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confidence: 78%

Negative normal stress differencesN₁–N₂in a low concentration capillary suspension

et al. 2018

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Here, negative normal stress differences are reported in capillary suspensions, i.e. particle suspensions in a two-fluid system that creates strong capillary attractions, at a solid concentration of 25%, and a volume fraction that has heretofore been considered too low to show such normal stress differences. Such capillary suspensions have strong particle networks and are shear thinning for the entire range of shear rates studied. Capillary suspensions exist in two states: a pendular state when the secondary fluid preferentially wets the particles, and a capillary state when the bulk fluid is preferentially wetting. In the pendular state, the system undergoes a transition from a positive normal stress difference at high shear rates to a negative stress difference at low shear rates. These results are an indication of flexible flocs in the pendular state that are able to rotate to reorientate in the vorticity direction under shear. Analogous experiments were also conducted for the capillary state, where only a negative normal stress difference occurs. The capillary state system forms more network contacts due to droplet breakup at higher shear rates, which enhances the importance of hydrodynamic interactions in the non-colloidal suspension.

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“…These include self-assembly of chiral aggregates of porphyrins, 68,69 formation of cylindrical flocs in water/oil 70 and colloidal 71 emulsions, or self-organization of sheared carbon nanotubes into ordered helical bands. 72 Such dissipative systems are ubiquitous in nature 73,74 and, for this reason, the observation of chiral bifurcation and flow-induced superstructures in conformational transitions of proteins should not be surprising. Very recently, Kawasaki et al 34 observed chiral bifurcation upon stirring of supersaturated cytosine solution, a finding that may bear enormous implications for understanding prebiotic origins of the homochirality of life.…”

Section: Discussionmentioning

confidence: 98%

Vortex-Induced Formation of Insulin Amyloid Superstructures Probed by Time-Lapse Atomic Force Microscopy and Circular Dichroism Spectroscopy

Loksztejn

Dzwolak

2010

Journal of Molecular Biology

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Ubiquity of domain patterns in sheared viscoelastic fluids

Cited by 23 publications

References 19 publications

Multiple Shear-Banding Transitions in a Supramolecular Polymer Solution

Multiple Shear-Banding Transitions in a Supramolecular Polymer Solution

Negative normal stress differencesN₁–N₂in a low concentration capillary suspension

Vortex-Induced Formation of Insulin Amyloid Superstructures Probed by Time-Lapse Atomic Force Microscopy and Circular Dichroism Spectroscopy

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Ubiquity of domain patterns in sheared viscoelastic fluids

Cited by 23 publications

References 19 publications

Multiple Shear-Banding Transitions in a Supramolecular Polymer Solution

Multiple Shear-Banding Transitions in a Supramolecular Polymer Solution

Negative normal stress differencesN1–N2in a low concentration capillary suspension

Vortex-Induced Formation of Insulin Amyloid Superstructures Probed by Time-Lapse Atomic Force Microscopy and Circular Dichroism Spectroscopy

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Negative normal stress differencesN₁–N₂in a low concentration capillary suspension