Rheology and Structure of Cornstarch Suspensions in Water-Poly(propylene glycol) Mixtures

Taylor, Spencer E.

doi:10.1080/01932691.2012.731634

Cited by 11 publications

(5 citation statements)

References 34 publications

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“…For Φ m EtOH above ∼20-25% these suspensions all present a yield stress and can be described by a simple Bingham equation : η B = η pl +σ Y / γ, in which η pl is the plastic viscosity and σ Y the yield stress. This is consistent with earlier observations in CS suspensions with {water/polypropylene glycol} solutions [17]. For lower Φ m EtOH , a Bingham equation can also approximate the flow curves for low shear rates.…”

Section: )As φ Msupporting

confidence: 92%

“…The archetypical suspension of CS grains in water exhibits a strong dynamic shear-thickening [3,[6][7][8]. Interestingly, Taylor [17] shows that replacing water by polypropylene glycol in CS suspensions completely suppresses its shear-thickening nature and modifies its dielectric properties, reminiscent of observations in thermal suspensions [18,19]. Consequently, we tune particle interactions using suspending fluids with different chemical but similar physical properties (density, viscosity.…”

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Dramatic effect of fluid chemistry on cornstarch suspensions: Linking particle interactions to macroscopic rheology

et al. 2017

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Suspensions of cornstarch in water exhibit strong dynamic shear-thickening. We show that partly replacing water by ethanol strongly alters the suspension rheology. We perform steady and nonsteady rheology measurements combined with atomic force microscopy to investigate the role of fluid chemistry on the macroscopic rheology of the suspensions and its link with the interactions between cornstarch grains. Upon increasing the ethanol content, the suspension goes through a yield-stress fluid state and ultimately becomes a shear-thinning fluid. On the cornstarch grain scale, atomic force microscopy measurements reveal the presence of polymers on the cornstarch surface, which exhibit a cosolvency effect. At intermediate ethanol content, a maximum of polymer solubility induces high microscopic adhesion which we relate to the macroscopic yield stress.Suspensions are mixtures of undissolved particles in a liquid. They are literally found all around us: mud, paints, pastes and blood [1]. The viscosity of a dense suspension can vary by orders of magnitude in a small shear rate interval [2]. Subjected to an increasing shear rate, dense suspensions first tend to become less viscous (shear-thinning) and then more viscous (shearthickening). The viscosity of some suspensions, especially non-Brownian ones, may increase so much that they effectively become solid [3]. Although standard rheology measurements provide a great tool to study this phenomenon [e.g. 4, 5], they are mainly limited to steadystate conditions.Many studies point out that dense suspensions exhibit remarkable dynamic phenomena emerging under non-steady-shear conditions: stable holes in thin vibrated layers [6], non-monotonic settling [7], dynamic compaction front [8] or fracturing [3]. Oscillatory rheology helps to describe some of these dynamic behaviours [9], but remains limited to constant volume conditions. Dynamic shear-thickening has been widely investigated [10], but its physical origin remains an active debate. Although several parameters seem to contribute to it (e.g. particles size [11], shape [12] or roughness [13]), it has become increasingly clear that frictional and non-contact interactions between particles play a key role [14,15]. Such interactions are easily modified in numerical simulations, but present a real challenge in experiments. Consequently, only few experimental studies addressthe role of particle-particle interactions in dense suspensions rheology [e.g. 5, 16] however lacking systematic variation of these interactions. Moreover, direct measurements of these interactions in relation to the rheology are also lacking so far.Here, we directly probe the microscopic interactions between individual particles and explore their link with * adeline.pons@normalesup.org the macroscopic rheology for dense cornstarch (CS) suspensions. The archetypical suspension of CS grains in water exhibits a strong dynamic shear-thickening [3,[6][7][8]. Interestingly, Taylor [17] shows that replacing water by polypropylene glycol in CS suspensions completely su...

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confidence: 99%

Dramatic effect of fluid chemistry on cornstarch suspensions: Linking particle interactions to macroscopic rheology

et al. 2017

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“…Since the transition temperature of cornstarch is independent of pH value, there is no differences according to pH value (Shim and Mulvaney, 2001). As the isoelectric point of cornstarch was found at pH 2.6 (Taylor, 2013), the increment of pH value above 2.6 showed the high water-holding ability.…”

Section: Discussionmentioning

confidence: 95%

Influence of the pH and Salt Concentrations on Physicochemical Properties of Pork Myofibrillar Protein Gels Added with Cornstarch

Lee¹,

Chin²

2020

Food Sci Anim Resour

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The aim of this study was to evaluate quality characteristics of pork myofibrillar protein (MP) added with cornstarch as affected by different pH values and salt cocnentrations. MP mixtures were prepared with three different pH values (pH 6.00, 6.25, and 6.50) and three different salt concentrations (0.15, 0.30, and 0.45 M). Cooking yield (CY), gel strength, viscosity, and scanning electron microscopy were measured to evaluate characteristics of MPs. CYs of MPs with cornstarch at above pH 6.25 or salt 0.30 M were increased compared to those at pH 6.00 or salt 0.15 M. However, gel strengths of MPs at salt 0.45 M were higher than those at salt 0.30 M. In microstructure analysis, MP gels with increasing pH value and salt concentration showed compact and uniform structure. Thus, MP gels with pH 6.25 and salt concentration of 0.30 M would be better for manufacturing meat products containing cornstarch to increase their water holding ability.

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“…As a result the shear thickening is masked. Apart from this qualitative explanation in terms of the hydrocluster mechanism, it is important to remark that a more efficient electrostatic stabilization in G/W mixtures is also expected since hydroxyl groups available onto the starch particles could form hydrogen bonds with polar molecules in G/W carriers [54,55]. f All tribological measurements were carried out in a non-conforming PDMS ballon-three-plates geometry.…”

Section: Resultsmentioning

confidence: 99%

Soft lubrication of cornstarch-based shear-thickening fluids

Ortigosa-Moya

Shahrivar

Hidalgo‐Álvarez

et al. 2019

Smart Mater. Struct.

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The behavior of complex fluids in thin films under the isoviscous elastohydrodynamic lubrication regime is a topic of current interest. A vast majority of the materials used to lubricate compliant contacts are shear-thinning fluids and, in comparison, very little is known about the lubrication properties of shear-thickening (ST) fluids. In this work we carried out both rheological and tribological experiments on ST fluids based on cornstarch suspensions. We investigated the influence of the polarity and viscosity of the carrier fluid and the cornstarch particles' concentration. From a rheological perspective, the ST response is diminished (as the shear-thinning region enlarges) when non-polar carriers are used (e.g. silicone oil) while a marked thickening is observed for polar carriers (e.g. glycerol-water mixtures). From a tribological perspective, the friction coefficient at slow sliding speeds is strongly affected by the nature of the carrier fluid, and in particular its wettability in contact with hydrophobic PDMS tribopairs. We demonstrate that experimental data, plotted in terms of Stribeck curves, provide useful information on the entrainment of particles/fluid through the contact. Finally, experimental results are also compared with numerical solutions of the Reynolds equation for inelastic non-Newtonian fluids in the isoviscous elastohydrodynamic regime. A Carreau-Yasuda constitutive equation for the viscosity-shear rate relationship is used.

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Rheology and Structure of Cornstarch Suspensions in Water-Poly(propylene glycol) Mixtures

Abstract: Concentrated aqueous cornstarch (CS) suspensions are often used to demonstrate an extreme example of shear thickening rheological behaviour. Here, we describe the increased rheological complexity that occurs on the addition of poly(propylene glycol)

Cited by 11 publications

References 34 publications

Dramatic effect of fluid chemistry on cornstarch suspensions: Linking particle interactions to macroscopic rheology

Dramatic effect of fluid chemistry on cornstarch suspensions: Linking particle interactions to macroscopic rheology

Influence of the pH and Salt Concentrations on Physicochemical Properties of Pork Myofibrillar Protein Gels Added with Cornstarch

Soft lubrication of cornstarch-based shear-thickening fluids

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