Untitled

Uriev, N. B.; Trofimova, L. E.

doi:10.1023/a:1024223310306

Cited by 4 publications

(4 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[64][65][66] A number of previous reports have observed a similar "viscosity anomaly" associated with the onset of shear banding. 35,[67][68][69][70][71][72] No clear evidence of banding texture was observed by direct observation, but the mechanism of individual sliding layers above a critical rate of deformation appears to be consistent with the microstructure of the smectic liquid crystals here. Further studies incorporating in situ light scattering or SAXS measurements during shear deformation, and potentially velocity tracking measurements, will be necessary to directly identify the length scale associated with the banding texture, if present.…”

Section: Steady Shear Viscositysupporting

confidence: 62%

“…Based on the previous work, the negative slope of shear stress (decreasing stress with increasing shear rate) is attributed to a mechanical instability associated with a non-uniform velocity prole through the gap of the instrument. 67,68,73 Olmsted proposed a general constitutive relationship to account for this behaviour based on the co-existence of multiple "phases" with distinct viscosities at a given shear rate (or shear stress). 74 In this context, the anomalous shape of the ow curves for the concentrated group of smectic suspensions may be attributed to a transition between microstructural "regimes," as suggested in Fig.…”

Section: Steady Shear Viscositymentioning

confidence: 99%

See 1 more Smart Citation

Interlayer structure and self-healing in suspensions of brush-stabilized nanoplatelets with smectic order

White

Wong

et al. 2015

Soft Matter

View full text Add to dashboard Cite

We have investigated the rheology of an uncured epoxy fluid containing high aspect ratio (length/thickness ≈ 160) α-zirconium phosphate (ZrP) nanoplatelets with smectic order. The nanoplatelets were exfoliated into monocrystalline sheets with uniform thickness using a monoamine-terminated oligomer. The oligomers were densely grafted to the plate surfaces and behave as a molecular brush. Suspensions containing ∼ 2 vol.% ZrP and above show liquid crystalline order with scattering peaks characteristic of a smectic (layered) mesophase. At much higher loading, ∼ 4 vol.% ZrP, there is a sharp transition in visual appearance, steady shear rheology, and linear and non-linear viscoelasticity that is attributed to the reversible interdigitation of oligomer chains between closely spaced layers. The oligomers are proposed to serve as inter-lamellar bridges that store elastic stresses for intermediate rates of deformation, but are able to relax on longer time scales. Under steady shearing conditions, the smectic suspensions with "overlapped" microstructure show a discontinuous flow curve characteristic of shear banding that is attributed to the dynamic pull-out of oligomer chains from the overlap region. At high shear rates, the limiting viscosity of the concentrated suspensions is on the same order of magnitude as the unfilled suspending fluid. When the rate of deformation is reduced below a critical time scale, the original network strength, and corresponding microstructure, is recovered through a passive self-healing process. The unique combination of concentration-dependent yield stress, low post-yield viscosity, and self-healing is potentially useful for various applications in the liquid state, and desirable for scalable processing of nanocomposite materials for structural applications.

show abstract

Section: Steady Shear Viscositysupporting

confidence: 62%

Section: Steady Shear Viscositymentioning

confidence: 99%

Interlayer structure and self-healing in suspensions of brush-stabilized nanoplatelets with smectic order

White

Wong

et al. 2015

Soft Matter

View full text Add to dashboard Cite

show abstract

“…Evidence for the occurrence of shear banding in solutions of entangled wormlike surfactant micelles (the shear stress minimum has been linked to the micelles becoming aligned in the flow) was obtained from NMR microscopy measurements of the velocity distribution in solutions in a cone and plate rheometer during shear . Flocculated suspensions have also been found to show anomalous flow behavior, and this was related to structural changes in the dispersions (see ref and references therein).…”

Section: Resultsmentioning

confidence: 99%

Rheological Behavior of Water-in-Oil Emulsions Stabilized by Hydrophobic Bentonite Particles

2005

View full text Add to dashboard Cite

A study of the rheological behavior of water-in-oil emulsions stabilized by hydrophobic bentonite particles is described. Concentrated emulsions were prepared and diluted at constant particle concentration to investigate the effect of drop volume fraction on the viscosity and viscoelastic response of the emulsions. The influence of the structure of the hydrophobic clay particles in the oil has also been studied by using oils in which the clay swells to very different extents. Emulsions prepared from isopropyl myristate, in which the particles do not swell, are increasingly flocculated as the drop volume fraction increases and the viscosity of the emulsions increases accordingly. The concentrated emulsions are viscoelastic and the elastic storage and viscous loss moduli also increase with increasing drop volume fraction. Emulsions prepared from toluene, in which the clay particles swell to form tactoids, are highly structured due to the formation of an integrated network of clay tactoids and drops, and the moduli of the emulsions are significantly larger than those of the emulsions prepared from isopropyl myristate.

show abstract

“…However, at φ N 60% and low σ, a substantial deviation from this dependence was observed, and the curve has a plateau, which can be attributed to a discontinuity of the structure. The analysis of this phenomenon for well-characterised disperse systems and systems formed by poly-dispersed particles (in some cases, by anisometric particles) was given in [13,14]. The conditions determining the possibility of discontinuity under deformation of concentrated disperse systems were analysed in [15].…”

Section: Models Of the Structured Disperse Systems Flowmentioning

confidence: 99%

Modelling of flow processes of the structured two-phase disperse systems (solid phase–liquid medium)

Uriev

Kuchin

2007

Advances in Colloid and Interface Science

View full text Add to dashboard Cite

Untitled

Cited by 4 publications

References 3 publications

Interlayer structure and self-healing in suspensions of brush-stabilized nanoplatelets with smectic order

Interlayer structure and self-healing in suspensions of brush-stabilized nanoplatelets with smectic order

Rheological Behavior of Water-in-Oil Emulsions Stabilized by Hydrophobic Bentonite Particles

Modelling of flow processes of the structured two-phase disperse systems (solid phase–liquid medium)

Contact Info

Product

Resources

About