Nonlinear rheological behavior of a concentrated spherical silica suspension

Watanabe, Hiroshi; Yao, Min; Yamagishi, A.; Osaki, Kunihiro; Shitata, Toshiyuki; Niwa, Hirokazu; Morishima, Yotaro

doi:10.1007/bf00368994

Cited by 60 publications

(74 citation statements)

References 37 publications

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“…In the literature, one can find numerous references (Inoubli et al 2006;Shikata and Pearson 1994;van der Werff et al 1989;Graebling et al 1993;Watanabe et al 1996;VignauxNassiet et al 1998) on suspensions showing secondary relaxation processes which are similar to the one described in this paper. Watanabe et al (1997) discuss the frequency dependence of the storage and loss moduli G and G of spherical styrene-isoprene micelles randomly dispersed in a nonentangling homopolyisoprene matrix.…”

Section: Discussionsupporting

confidence: 72%

“…Strain-induced disturbances of the homogeneous particle distributions are expected to generate the Brownian stress. The Brownian stress relaxation has already been observed in concentrated spherical silica suspensions (Watanabe et al 1996;Shikata and Pearson 1994). The main purpose of the present paper is to elucidate whether the Brownian stress relaxation takes influence on the rheological behavior of the DGEBA-SiO 2 composites and, if so, how it competes with the underlying α-process of the DGEBA matrix.…”

Section: Introductionmentioning

confidence: 83%

“…Due to the large size of the silica particles, the Brownian diffusion effects could be neglected. (ii) The investigation of linear viscoelastic behavior of concentrated submicron silica suspensions in supercooled ethylene glycol/glycerol mixtures (Shikata and Pearson 1994, Watanabe et al 1996 revealed the existence of a low-frequency relaxation process. The authors describe the colloids as viscoelastic suspensions of hard-sphere like Brownian particles with no long-range interaction (except the hydrodynamic interaction) and attribute the process to the relaxation of the shear-induced anisotropy in the distribution of particle positions.…”

Section: Discussionmentioning

confidence: 99%

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Strain-induced low-frequency relaxation in colloidal DGEBA/SiO2 suspensions

et al. 2014

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Diglycidyl ether of bisphenol A (DGEBA) is widely exploited as an epoxy resin in adhesives and coatings. In this paper, it is used as an oligomer matrix for silicafilled nanocomposites. Rheological measurements show that the pure matrix obeys power-law relaxation dynamics in the vicinity of the dynamic glass transition of this lowmolecular-weight glass former. In the filled systems, a lowfrequency relaxation appears additionally to the structural α-process of the matrix. Considering the nanocomposites as Newtonian hard-sphere suspensions at low angular frequencies (or high temperatures), the modified terminal regime behavior of the matrix can be linked to strain-induced perturbations of the isotropic filler distributions. While in the low-frequency regime hydrodynamic stresses relax instantaneously, the Brownian stress relaxation is viscoelastic and can be evidenced by dynamic rheological measurements. At higher angular frequencies, the α-process of the matrix superimposes on the Brownian stress relaxation. In particular, we were able to depict the low-frequency anomaly for concentrated, semi-dilute, and even for dilute suspensions.

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Section: Discussionsupporting

confidence: 72%

Section: Introductionmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 99%

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Strain-induced low-frequency relaxation in colloidal DGEBA/SiO2 suspensions

et al. 2014

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“…A thorough review of traditional rheology techniques may be found in the work of Barnes et al (1989). Transient flows also give insight into the micromechanics of rate-dependent processes in steady-state flow behavior: Sudden removal of external forcing demonstrates that the microstructure relaxes over multiple time scales, each associated with distinct physical processes [Mackay and Kaffashi (1995); Watanabe et al (1996aWatanabe et al ( , 1996b; Kaffashi et al (1997); Foss (1999); Zia and Brady (2013)]. Such temporal response reveals the underlying connection between structure and rheology.…”

Section: Introductionmentioning

confidence: 99%

Large amplitude oscillatory microrheology

Swan¹,

Zia²,

Brady³

2014

Journal of Rheology

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SynopsisWe study the motion of a colloidal particle as it is driven by an oscillating external force of arbitrary amplitude and frequency through a colloidal dispersion. Large amplitude oscillatory flows (LAOFs) are examined predominantly from a phenomenological perspective in which experimental measurements inform constitutive models. Here, we investigate a LAOF from a microstructural perspective by connecting motion of the probe particle to the material response while making no assumptions a priori about how stress relaxes in the material. The suspension exerts nonconservative, hydrodynamic forces on the probe, while distortions in the particle configuration exert conservative forces: Brownian and interparticle forces, for example. The relative importance of each of these contributions to particle motion evolves with the degree of displacement from equilibrium. When the force on the probe is weak, the linear microviscoelasticity of the suspension is probed [see, e.g., Khair and Brady, J. Rheol. 49, 1449-1481]. When oscillation rate is slow, the steady microrheology is probed [see, e.g., Squires and Brady, Phys. Fluids 17, 073101 (2005); Khair and Brady, J. Fluid Mech. 557, 73-117 (2006)]. This article develops a micromechanical model that recovers these limiting cases and then uses the same model to reveal the microrheology of colloidal dispersions deformed by a probe driven with arbitrary force amplitude and frequency. A chief result of this work is the discovery of a regime in which the resistance to motion of the probe particle is on average weaker than the resistance the probe experiences when deformed by high frequency oscillation. This hypoviscous effect arises when the reciprocating motion of the probe particle opens a a)

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“…1 Nonlinear rheological measurements can also be performed by significantly straining the material, which enables additional information to be obtained, such as shear thinning and shear thickening, 2,3 normal stress differences, 4 and relaxation processes. [5][6][7][8][9] However, some materials of interest ͑particularly biomaterials͒ are difficult to procure in the large quantities required for traditional rheometers. To address such issues, techniques encompassing "microrheology" are being developed using small colloidal beads as tracers.…”

Section: Introductionmentioning

confidence: 99%

A simple paradigm for active and nonlinear microrheology

Squires¹,

Brady²

2005

Physics of Fluids

238

383

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In microrheology, elastic and viscous moduli are obtained from measurements of the fluctuating thermal motion of embedded colloidal probes. In such experiments, the probe motion is passive and reflects the near-equilibrium ͑linear response͒ properties of the surrounding medium. By actively pulling the probe through the material, further information about material properties can be obtained, analogous to large-amplitude measurements in ͑macro-͒ rheology. We consider a simple model of such systems: a colloidal probe pulled through a suspension of neutrally buoyant bath colloids. We choose a system with hard-sphere interactions but neglect hydrodynamic interactions, which is simple enough to permit analytic solutions, but nontrivial enough to raise issues important for the interpretation of experiments in active and nonlinear microrheology. We calculate the microstructural deformation for arbitrary probe size and pulling rate ͑expressed as a dimensionless Péclet number Pe͒. From this, we determine the average retarding effect on the probe due to the microstructure, as well as fluctuations about this average. The high-Pe limit is singular, giving a finite Brownian contribution even in the limit of negligible diffusion. Significantly, different results are obtained for probes driven at constant velocity and constant force. Furthermore, we demonstrate that a probe pulled with an optical tweezer ͑roughly a harmonic well͒ can behave as fixed-force, fixed-velocity, or as a mixture of those modes, depending on the strength of the trap and on the pulling speed. More generally, we discuss how these results relate to previous work on the rheology of colloidal suspensions. Not surprisingly, the present theory ͑which ignores hydrodynamic interactions͒ gives shear thinning but no shear thickening; we expect that the incorporation of hydrodynamics would result in shear thickening as well. The effective micro-and macro-viscosities, when appropriately scaled, are in semi-quantitative agreement. This seems remarkable, given the rather significant difference in the two methods of measurement. However, for more complicated or unknown materials, where such scaling relations may not be known in advance, the comparison between micro-and macro may not be so favorable, which raises important questions about the relation between micro-and macrorheology. Finally, by analogy with previous work on macrorheology, we propose methods to scale up the present ͑dilute͒ theory to account for more concentrated suspensions, and suggest new active microrheological experiments to probe different aspects of suspension behavior.

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Nonlinear rheological behavior of a concentrated spherical silica suspension

Cited by 60 publications

References 37 publications

Strain-induced low-frequency relaxation in colloidal DGEBA/SiO2 suspensions

Strain-induced low-frequency relaxation in colloidal DGEBA/SiO2 suspensions

Large amplitude oscillatory microrheology

A simple paradigm for active and nonlinear microrheology

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