The primary electroviscous effect in a sulfonated polystyrene latex

Chan, F. S.; Goring, D. A. I.

doi:10.1016/0021-9797(66)90017-8

Cited by 37 publications

(10 citation statements)

References 27 publications

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“…In these experiments, the shear viscosity of the bulk dispersion can be determined independently from the near surface layer and apparent boundary effects. The value of the apparent volume fraction increment, p, is 0.55 in the fully deionized sample and similar to that reported by Rubio-Hernańdez et al 24 for a weakly charged sulfonated latex. The value of p is larger than that calculated by simple theory such as that of Watterson and White; 29 previously, such values have been ascribed to the effects of nonuniformity and particle roughness.…”

Section: ■ Results and Discussionsupporting

confidence: 89%

“…The increase in viscosity is expected and originates in particles getting more crowded at higher concentrations. Charged colloidal particles dispersed in an electrolyte have been studied by many groups, and it is recognized that the viscosity of these dispersions depends strongly on the volume fraction and the excess electrolyte concentration. − There are also distinct electroviscous effects that alter both the extent of the diffuse double layer of ions surrounding each particle, known as the primary effect, and the secondary effect of electrostatic repulsion between the particles causing local differences in the velocities of particles and the surrounding fluid. The viscosity of dilute dispersions (below φ = 0.1) of hard spheres can be described according to Einstein’s viscosity equation: η = (1 + 2.5φ particles )η solvent , where η is the viscosity and φ is the volume fraction of the particles in a Newtonian liquid with viscosity η solvent .…”

Section: Resultsmentioning

confidence: 99%

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Charged Polystyrene Nanoparticles Near a SiO₂/Water Interface

Hellsing

Rennie

Rodal³

et al. 2018

Langmuir

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Quartz crystal microbalance with dissipation (QCM-D) monitoring is used to investigate the adsorption processes at liquid–solid interfaces and applied increasingly to characterize viscoelastic properties of complex liquids. Here, we contribute new insights into the latter field by using QCM-D to investigate the structure near the interface and the high-frequency viscoelastic properties of charge-stabilized polystyrene particles (radius 37 nm) dispersed in water. The study reveals changes with increasing ionic strength and particle concentration. Replacing water with a dispersion is usually expected to give rise to a decrease in frequency, f. Increases in both f and dissipation, D, were observed on exchanging pure water for particle dispersions at a low ionic strength. The QCM-D data are well-represented by a viscoelastic model, with viscosity increasing from 1.0 to 1.3 mPa s as the particle volume fraction changes from 0.005 to 0.07. This increase, higher than that predicted for noninteracting dispersions, can be explained by the charge repulsion between the particles giving rise to a higher effective volume fraction. It is concluded that the polystyrene particles did not adhere to the solid surface but rather were separated by a layer of pure dispersion medium. The QCM-D response was successfully represented using a viscoelastic Kelvin–Voigt model, from which it was concluded that the thickness of the dispersion medium layer was of the order of the particle–particle bulk separation, in the range of 50–250 nm, and observed to decrease with both particle concentration and addition of salt. Similar anomalous frequency and dissipation responses have been seen previously for systems containing weakly adherent colloidal particles and bacteria and understood in terms of coupled resonators. We demonstrate that surface attachment is not required for such phenomena to occur, but that a viscoelastic liquid separated from the oscillating surface by a thin Newtonian layer gives rise to similar responses.

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Section: ■ Results and Discussionsupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Charged Polystyrene Nanoparticles Near a SiO₂/Water Interface

Hellsing

Rennie

Rodal³

et al. 2018

Langmuir

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“…D. Sherwood mental results for the electroviscous effect are tabulated in table 2 and plotted on figure 10. The agreement between theory and experiment is as good as that obtained by Chan & Goring (1966) or by Stone-Masui & Watillon (1968). Here we have the experimental advantage that the electroviscous effect is larger than the intrinsic viscosity of the uncharged molecules.…”

Section: Rods With No-slip Boundary Conditionssupporting

confidence: 85%

The primary electroviscous effect in a suspension of rods

Sherwood

1981

J. Fluid Mech.

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Calculations of the primary electroviscous effect have previously been restricted to spherical particles. Here we examine a suspension of randomly orientated rod-shaped particles of length l. Two competing mechanisms are present in a linear velocity field. The flow relative to each rod is largest at the rod ends. When l is large the consequent large distortion of the charge cloud increases the electroviscous effect. On the other hand, the given total charge on a uniformly charged rod is spread more thinly as l increases, and this tends to reduce the electroviscous effect. The balance of these two mechanisms is examined.

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“…Chan et al . used sulfonated polystyrene latex particles to study the influence of PEE on viscosity by varying ionic strength, and their results (PEE) were shown to be comparable (with experimental error) to the theoretical predictions from the equations of Smoluchowski and Booth (Chan and Goring, 1966). As for concentrated protein formulations, electroviscous effect (it is really referred to PEE in many papers) is considered not important, completely neglecting SEE (Zhang and Liu, 2017).…”

Section: Electroviscous Effectmentioning

confidence: 82%