Über die Elastizität von Solen und Gelen

Freundlich, H.; Seifriz, William

doi:10.1515/zpch-1923-10415

Cited by 66 publications

(23 citation statements)

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“…This includes hydrodynamic diffusion, polydisperse sedimentation, high‐frequency linear viscoelasticity, shear thinning, and shear thickening . Microrheology theory for dilute suspensions has been tested and validated in the experimental literature, including cells, actin networks, gelatin, DNA and polyethylene oxide solutions, wormlike micelles and polymer solutions, nonequilibrium behaviors in colloids, the behavior of colloids near glass transition, fundamental interaction between pairs of colloids, and entropic forces in binary colloids …”

Section: Theoretical Frameworkmentioning

confidence: 99%

The impact of hydrodynamics on viscosity evolution in colloidal dispersions: Transient, nonlinear microrheology

Mohanty

Zia

2018

AIChE Journal

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Evolution of microstructure and rheology during flow startup, and its connection to microscopic transport processes, is studied theoretically via active microrheology. At steady state, the balance between entropic, hydrodynamic, and other forces changes with flow strength, producing sustained microstructural asymmetry and non-Newtonian rheology. However, the transition from equilibrium to steady flow is sometimes marked by overshoots in viscosity that suggests a temporally evolving competition between these rate processes. Here, we formulate and solve a Smoluchowski equation for the time-dependent evolution of particle microstructure induced by the motion of a colloidal probe driven through a bath of colloidal spheres. The structure is then utilized to compute the time-dependent microviscosity. Brownian diffusion always sets short-time particle dynamics, which hinders maturation of the boundary layer. The disparity in Brownian and advective transport rates produces a reversal from flow thinning to flow thickening during startup, revealing that non-Newtonian flow phenomenology is not instantaneously established. Figure 4. The evolution of the Brownian viscosity, η B =η s ϕ, at arbitrary Pe and strong hydrodynamics (κ !0) is plotted vs. advectively scaled time in (a) and (b), and vs. diffusively scaled time in (c) and (d). Péclet numbers corresponding to the curves are labeled at the bottom of the figure. [Color figure can be viewed at wileyonlinelibrary.com]

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Section: Theoretical Frameworkmentioning

confidence: 99%

The impact of hydrodynamics on viscosity evolution in colloidal dispersions: Transient, nonlinear microrheology

Mohanty

Zia

2018

AIChE Journal

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“…Passive microrheology can be used to interrogate linear viscoelasticity [Mason and Weitz (1995)]; recent studies also account for the effect of probe size [Lu and Solomon (2002)] and shape [Khair and Brady (2008)]. Microrheological techniques have been used to study cells [Bausch et al (1998); Guilford et al (1995); Lau et al (2003)], actin networks [Gisler and Weitz (1999); Ziemann et al (1994)], gelatin [Freundlich and Seifriz (1923)], DNA and polyethylene oxide solutions [Mason et al (2005)], the glass transition in colloids [Habdas et al (2004)], as well as fundamental interactions between pairs of colloidal spheres [Crocker (1997); Crocker et al (2000); Levine and Lubensky (2000)] and entropic forces in binary colloids [Crocker et al (1999)]. Microrheology has also been proposed as a tool for high-throughput material screening [Breedveld and Pine (2003); Schultz and Furst (2011)].…”

Section: Introductionmentioning

confidence: 99%

Stress development, relaxation, and memory in colloidal dispersions: Transient nonlinear microrheology

Zia¹,

Brady²

2013

Journal of Rheology

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Performance of mesoscale modeling methods for predicting rheological properties of charged polystyrene/water suspensions J. Rheol. 56, 353 (2012) Three-dimensional flow of colloidal glasses J. Rheol. 56, 259 (2012) Emergence of turbid region in startup flow of CTAB/NaSal aqueous solutions between parallel plates J. Rheol. 56, 245 (2012) Nonlinear rheology and yielding in dense suspensions of hard anisotropic colloids J. Rheol. 55, 1069Rheol. 55, (2011 Additional information on J. Rheol. SynopsisThe motion of a single Brownian particle in a complex fluid can reveal material behavior both at and away from equilibrium. In active microrheology, a probe particle is driven by an external force through a complex medium and its motion studied in order to infer properties of the embedding material. Most work in microrheology has focused on steady behavior and established the relationship between the motion of the probe, the microstructure, and the effective microviscosity of the medium. Transient behavior in the near-equilibrium, linear-response regime has also been studied via its connection to low-amplitude oscillatory probe forcing and the complex modulus; at very weak forcing, the microstructural response that drives viscosity is indistinguishable from equilibrium fluctuations. But important information about the basic physical aspects of structural development and relaxation in a medium is captured by startup and cessation of the imposed deformation in the nonlinear regime, where the structure is driven far from equilibrium. Here, we study theoretically and by dynamic simulation the transient behavior of a colloidal dispersion undergoing nonlinear microrheological forcing. The strength with which the probe is forced, F ext , compared to thermal forces, kT/b, governs the dynamics and defines a P eclet number, Pe ¼ F ext =ðkT=bÞ, where kT is the thermal energy and b is the colloidal bath particle size. For large Pe, a boundary layer (in which unsteady advection balances diffusion) forms at particle contact on the time scale of the flow, a/U, where a is the probe size and U its speed, whereas the wake forms over O(Pe) diffusive time steps. Similarly, relaxation following cessation occurs over several time scales corresponding to distinct physical processes. For very short times, the time scale for relaxation is set by a boundary layer of thickness d $ ða þ bÞ=Pe, and so s $ d 2 =D r , where D r is the relative diffusivity between the probe of size a and a bath particle. Nearly all stress relaxation occurs during this time. At longer times, the Brownian diffusion of the bath particles acts to close the wake on a time scale set by how long it takes a bath particle to diffuse laterally across it, s $ ða þ bÞ 2 =D r . Although the majority of the microstructural relaxation occurs during this wakehealing process, it does so with little change in the stress. Also during relaxation, the probe travels backward in the suspension; this recovered strain is proportional to the free energy stored in the a) Author to who...

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“…Much work has since followed, including the extension of the Stokes-Einstein relation to viscoelastic materials [Mason and Weitz (1995)], and studies of the effect of probe size [Lu and Solomon (2002)] and shape [Khair and Brady (2008)]. Microrheological techniques have been used to study a diverse set of systems: cells [Bausch et al (1998); Guilford et al (1999); Lau et al (2003)], actin networks [Gisler and Weitz (1999); Ziemann et al (1994)], gelatin [Freundlich and Seifriz (1923)], deoxyribose nucleic acid (DNA) and polyethylene oxide solutions [Mason et al (2005)], and the behavior of colloids near the glass transition [Habdas et al (2004)], as well as fundamental interactions between pairs of colloidal spheres [Crocker (1997); Crocker et al (2000); Levine and Lubensky (2000)] and entropic forces in binary colloids [Crocker et al (1999)]. Microrheology has also been proposed as a tool for studying basic physics in atomic or molecular systems and for high-throughput material screening [Breedveld and Pine (2003); Schultz and Furst (2011)].…”

Section: Introductionmentioning

confidence: 99%