Dynamics of dense, charge-stabilized suspensions of colloidal silica studied by correlation spectroscopy with coherent X-rays

Grübel, G.; Abernathy, D. L.; Riese, D.O.; Vos, Willem L.; Wegdam, G.H.

doi:10.1107/s0021889800099994

Cited by 40 publications

(28 citation statements)

References 14 publications

(18 reference statements)

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“…The system with Z = 10 is practically hard-sphere-like ͓see Fig. 12͑b͔͒ 41 this behavior was erroneously interpreted to be in contradiction to the expected one, i.e., to an H͑q m ͒ that should increase with volume fraction as observed for the more dilute samples studied in Refs. 43 and 44.…”

Section: F Discussion Of Earlier Experiments: Does His Screening Occur?mentioning

confidence: 82%

Collective diffusion in charge-stabilized suspensions: Concentration and salt effects

Gapiński

Patkowski

Banchio

et al. 2007

The Journal of Chemical Physics

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The authors present a joint experimental-theoretical study of collective diffusion properties in aqueous suspensions of charge-stabilized fluorinated latex spheres. Small-angle x-ray scattering and x-ray photon correlation spectroscopy have been used to explore the concentration and ionic-strength dependence of the static and short-time dynamic properties including the hydrodynamic function H͑q͒, the wave-number-dependent collective diffusion coefficient D͑q͒, and the intermediate scattering function over the entire accessible range. They show that all experimental data can be quantitatively described and explained by means of a recently developed accelerated Stokesian dynamics simulation method, in combination with a modified hydrodynamic many-body theory. In particular, the behavior of H͑q͒ for de-ionized and dense suspensions can be attributed to the influence of many-body hydrodynamics, without any need for postulating hydrodynamic screening to be present, as it was done in earlier work. Upper and lower boundaries are provided for the peak height of the hydrodynamic function and for the short-time self-diffusion coefficient over the entire range of added salt concentrations.

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Section: F Discussion Of Earlier Experiments: Does His Screening Occur?mentioning

confidence: 82%

Collective diffusion in charge-stabilized suspensions: Concentration and salt effects

Gapiński

Patkowski

Banchio

et al. 2007

The Journal of Chemical Physics

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“…It is thus not surprising that the model fails to describe the data. There is no evidence that these deviations would be caused by magnetic effects since similar observations are reported also for non-magnetic particles (Riese, 2000;Grü bel et al, 2000). There it is argued that the hydrodynamics of concentrated suspensions of highly-charged particles show resemblance to hard-sphere hydrodynamics, however with an additional retardation caused by the charge-stabilized character of the systems.…”

Section: Figurementioning

confidence: 86%

The dynamic behavior of magnetic colloids in suspension

Autenrieth¹,

Robert

Wagner

et al. 2007

J Appl Cryst

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The dynamic behavior of magnetic colloidal particles in suspension is investigated. The particles of the core-shell colloid consist of a cobalt ferrite core embedded in a silica shell and are stabilized by surface charges. As the suspension is strongly opaque to visible light, it can not be probed by dynamic light scattering techniques as a result of strong multiple scattering as well as absorption effects. Therefore, the static and dynamic behavior is probed with small-angle X-ray scattering and X-ray photon correlation spectroscopy (XPCS), respectively. Using XPCS, we are able to study the diffusion coefficient of an opaque colloidal system as a function of the scattering vector. In this paper, we report on the behavior of the colloidal system in the absence of an external magnetic field, meaning that the magnetic moments of the particles are oriented randomly. We find no evidence for magnetic interactions in the static data, while the dynamic XPCS data deviate very significantly from the predictions of model calculations.

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“…The majority of earlier work was concerned with systems showing peak heights in H͑q͒ not far from the corresponding equal-concentration hard-sphere values. 5,6 In some earlier work, strikingly low peak values of H͑q͒ have been reported to occur in dense low-salt systems, [7][8][9][10] an observation which was interpreted initially in terms of hydrodynamic screening. 11 We show that all our experimental short-time diffusion data, obtained for three different series of samples, can be consistently explained by the renormalized density fluctuation expansion method of Beenakker and co-workers, spheres ͑HSs͒ only, but in later work its zeroth-order version was used to make predictions also for charge-stabilized systems.…”

Section: Introductionmentioning

confidence: 99%

Structure and short-time dynamics in suspensions of charged silica spheres in the entire fluid regime

Gapiński

Patkowski

Banchio

et al. 2009

The Journal of Chemical Physics

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We present an experimental study of short-time diffusion properties in fluidlike suspensions of monodisperse charge-stabilized silica spheres suspended in dimethylformamide. The static structure factor S͑q͒, the short-time diffusion function D͑q͒, and the hydrodynamic function H͑q͒ have been probed by combining x-ray photon correlation spectroscopy experiments with static small-angle x-ray scattering. Our experiments cover the full liquid-state part of the phase diagram, including de-ionized systems right at the liquid-solid phase boundary. We show that the dynamic data can be consistently described by the renormalized density fluctuation expansion theory of Beenakker and Mazur over a wide range of concentrations and ionic strengths. In accordance with this theory and Stokesian dynamics computer simulations, the measured short-time properties cross over monotonically, with increasing salt content, from the bounding values of salt-free suspensions to those of neutral hard spheres. Moreover, we discuss an upper bound for the hydrodynamic function peak height of fluid systems based on the Hansen-Verlet freezing criterion.

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Dynamics of dense, charge-stabilized suspensions of colloidal silica studied by correlation spectroscopy with coherent X-rays

Cited by 40 publications

References 14 publications

Collective diffusion in charge-stabilized suspensions: Concentration and salt effects

Collective diffusion in charge-stabilized suspensions: Concentration and salt effects

The dynamic behavior of magnetic colloids in suspension

Structure and short-time dynamics in suspensions of charged silica spheres in the entire fluid regime

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