Hydrodynamic and Colloidal Interactions in Concentrated Charge-Stabilized Polymer Dispersions

Horn, F. M.; Richtering, Walter; Bergenholtz, Johan; Willenbacher, Norbert; Wagner, Norman J.

doi:10.1006/jcis.1999.6705

Cited by 87 publications

(52 citation statements)

References 60 publications

(73 reference statements)

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“…(44)), reflecting the weaker hydrodynamic dissipation of in charged-sphere systems due to the depletion of neighboring spheres near contact caused by electrostatic repulsion. The experimental data in [76] and [92] conform with the theoretically predicted trends even at large values of φ. At very large volume fractions, however, many-body near-field HI come into play even in low-salt systems.…”

Section: High-frequency Limiting Viscositysupporting

confidence: 83%

Short-time transport properties in dense suspensions: From neutral to charge-stabilized colloidal spheres

Banchio

Nägele

2008

The Journal of Chemical Physics

173

319

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We present a detailed study of short-time dynamic properties in concentrated suspensions of charge-stabilized and of neutral colloidal spheres. The particles in many of these systems are subject to significant many-body hydrodynamic interactions. A recently developed accelerated Stokesian Dynamics (ASD) simulation method is used to calculate hydrodynamic functions, wavenumber-dependent collective diffusion coefficients, self-diffusion and sedimentation coefficients, and high-frequency limiting viscosities. The dynamic properties are discussed in dependence on the particle concentration and salt content. Our ASD simulation results are compared with existing theoretical predictions, notably those of the renormalized density fluctuations expansion method of Beenakker and Mazur, and earlier simulation data on hard spheres. The range of applicability, and the accuracy of various theoretical expressions for short-time properties, are explored through comparison with the simulation data. We analyze in particular the validity of generalized StokesEinstein relations relating short-time diffusion properties to the high-frequency limiting viscosity, and we point to the distinctly different behavior of de-ionized charge-stabilized systems in comparison to hard spheres.

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Section: High-frequency Limiting Viscositysupporting

confidence: 83%

Short-time transport properties in dense suspensions: From neutral to charge-stabilized colloidal spheres

Banchio

Nägele

2008

The Journal of Chemical Physics

173

319

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“…However, measurement of ϱ typically requires large volumes ͑у 20 mL͒, which were unfortunately not available to us due was indistinguishable from that of hard spheres. 63 The reason for the weak dependence of ϱ on ionic strength is first that ϱ depends only indirectly on DI, and second that ϱ is dominated by long-range HI and therefore not very sensitive to the microstructure. Therefore, it seems in our case a good strategy to compare the short-time diffusion results at all ionic strengths to ϱ of hard spheres.…”

Section: Comparison Between Rotational Tracer Diffusion and Host Suspmentioning

confidence: 99%

Rotational dynamics of charged colloidal spheres: Role of particle interactions

Koenderink

Lettinga

Philipse

2002

The Journal of Chemical Physics

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Time-resolved phosphorescence anisotropy ͑TPA͒ is used to measure the short-time rotational diffusion coefficient D s r () of charged tracer spheres as a function of the volume fraction of like-charged colloidal host spheres in nonaqueous solvents. Sphere interactions are varied from long-range repulsive to short-range attractive by changing the ionic strength and the solvent composition. It is shown that D s r () is very sensitive to details of the interaction near contact, in agreement with theory. In contrast, the low-shear viscosity L () of the host dispersions is mostly controlled by the tail of the interaction potential. We discuss the applicability of Stokes-EinsteinDebye scaling D s r ()ϰ1/ L (), and D s r ()ϰ1/ ϱ (), where ϱ is the high-frequency-limiting viscosity. Scaling with L () fails at high particle and low salt concentrations, while scaling with ϱ is fairly good, in particular when an apparent nonstick boundary condition is imposed on the friction factor. We conclude that TPA is well suited for use as a microrheological technique.

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“…We are not aware of any closed analytical expressions for Z 1 (f)/Z 0 of charged spheres with stronger screening of the electrostatic double layer repulsions. The few measurements available 22,33,34 suggest, however, that…”

mentioning

confidence: 99%

On the validity of Stokes–Einstein–Debye relations for rotational diffusion in colloidal suspensions

et al. 2002

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According to the Stokes-Einstein-Debye (SED) relation, the rotational diffusion coefficient of a colloidal tracer sphere scales with the inverse of the solvent viscosity. Here we investigate the generalization of the SED relation to tracer diffusion in suspensions of neutral and charged colloidal host spheres. Rotational diffusion coefficients are measured with dynamic light scattering and phosphorescence spectroscopy, and calculated including two-and three-particle hydrodynamic interactions. We find that rotational tracer diffusion is always faster than predicted by the SED relation, except for large tracer/host size ratios l. In the case of neutral particles this observation is rationalized by introducing an apparent l-dependent slip boundary coefficient. For charged spheres at low ionic strength, large deviations from SED scaling are found due to the strongly hindered host sphere dynamics. Finally, we present some first experiments on tracer sphere diffusion in suspensions of host rods, showing that hydrodynamic hindrance by rods is much stronger than by spheres. We conclude by pointing to some interesting unresolved issues for future research. I IntroductionThe rotational diffusion coefficient of a single colloidal sphere with radius a T suspended in a solvent with shear viscosity Z 0 is given by the familiar Stokes-Einstein-Debye (SED) relationwith k B T the thermal energy and f r 0 the Stokesian friction factor. Eqn. (1) assumes that the particle is large enough for the solvent to behave as a structureless continuum with vanishing response time. Moreover, stick boundary conditions are assumed, i.e. the velocity of the fluid on the tracer surface equals that of the tracer. Eqn. (1) holds quantitatively not only for colloidal particles but,

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Hydrodynamic and Colloidal Interactions in Concentrated Charge-Stabilized Polymer Dispersions

Cited by 87 publications

References 60 publications

Short-time transport properties in dense suspensions: From neutral to charge-stabilized colloidal spheres

Short-time transport properties in dense suspensions: From neutral to charge-stabilized colloidal spheres

Rotational dynamics of charged colloidal spheres: Role of particle interactions

On the validity of Stokes–Einstein–Debye relations for rotational diffusion in colloidal suspensions

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