Viscosity of bimodal charge-stabilized polymer dispersions

Horn, F. M.; Richtering, Walter

doi:10.1122/1.1308519

Cited by 17 publications

(12 citation statements)

References 30 publications

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“…The effect of different factors such as interparticle forces, Brownian motion of the particles, hydrodynamic interactions, as well as physical characteristics of the particles such as particle size, particle size distribution, and shape of the particles that govern the rheological behavior of colloidal dispersions, must be accordingly considered in the development of predictive theories and empirical models. It is widely known that the rheological behavior of colloidal dispersions is strongly affected by particle size polydispersity, and suspensions made of particles of different sizes have a significantly lower viscosity than the one containing only mono‐sized particles 1–12 . The viscosity of colloidal dispersions diverges at the maximum packing fraction where the behavior of the system changes from a liquid to a solid‐like behavior.…”

Section: Introductionmentioning

confidence: 99%

“…The model was proved to be inadequate for suspensions made of colloidal size particles. The role of electrostatic repulsion in the viscosity of bimodal colloidal dispersions has been investigated by some investigators 11–12 . Horn and Richtering 12 tried to apply our proposed scaling method to the zero shear rate viscosity of electrostatically stabilized dispersions of polymer lattices and showed that the model did not satisfactorily fit their experimental data and concluded that the scaling model may not be applied to bimodal dispersions at very low shear rates where colloidal forces are dominant.…”

Section: Introductionmentioning

confidence: 99%

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Viscosity of Electrostatically Stabilized Dispersions of Monodispersed, Bimodal, and Trimodal Silica Particles

Zaman

Dutcher

2005

Journal of the American Ceramic Society

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Effect of particle size and polydispersity on the viscosity and maximum packing fraction of aqueous colloidal dispersions has been studied. For dispersions of mono-sized particles, the results indicate that there is a linear relationship between the log(g) (viscosity) and particle size at a fixed shear rate and volume fraction of solids. However, there is a particle diameter at which there is a decrease in the dependency of viscosity on particle size as the slope of the linear plots of log(g) versus particle diameter changes to a smaller value. Preliminary calculations indicate that this particle size may correspond to a separation distance at which electrostatic energy as compared with the thermal energy of the particles can be ignored. In the case of bimodal dispersions, the viscosity is affected by both absolute size and the ratio of the two sizes. The effect of particle size ratio on the viscosity was investigated using bimodal dispersions of the same size coarse particles, but fines of different sizes. There is a critical volume ratio below which bimodal dispersions of larger size ratios show lower viscosities than systems of smaller size ratios. Above this volume ratio of the two sizes, the trend becomes reversed and the fines will have a dominant effect on the viscosity behavior of the bimodal system. Statistically designed experiments were carried out using trimodal mixtures of monodispersed silica particles and it was shown that tridispersed suspensions demonstrate similar behavior as bidispersed suspensions, with a minimum in viscosity observed as a function of particle volume ratio.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Viscosity of Electrostatically Stabilized Dispersions of Monodispersed, Bimodal, and Trimodal Silica Particles

Zaman

Dutcher

2005

Journal of the American Ceramic Society

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“…Equation (78) is often used to model both concentrated charged and hard sphere suspensions [88] [89] [90]. The zero-shear viscosities are extracted from well-defined Newtonian low-shear plateaus shown in Figure 20 for the all three dispersions investigated here.…”

Section: Rheological Estimation Of Electrostatic Double-layer Thicknessmentioning

confidence: 99%

Clogging of microchannels by nano-particles due to hetero-coagulation in elongational flow

Georgieva

Dijkstra

Fricke

et al. 2010

Journal of Colloid and Interface Science

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We have investigated the phenomenon of flow-induced aggregation in highly concentrated colloidal dispersions exposed to strongly converging flow fields. This phenomenon is relevant not only for classical technical operations like coating, pumping or filtration, but also for the application of concentrated suspensions in upcoming processing technologies based on microfluidic devices. A ring-slit device (gap height 10 micrometers to 25 micrometers), which allows for a variation of flow kinematics in a wide range, has been developed in order to investigate this phenomenon. Various polymer dispersions with different particle surface properties have been used as model systems. Our experiments exclude, that channel clogging is due to retention of pre-existing aggregates, fouling or hydrodynamic bridging. Instead, we demonstrate that clogging of the microchannel is induced by hetero-coagulation between primary colloidal particles and micron-sized impurities present at concentrations on the order of 100 ppm to 1000 ppm. Clogging can occur even if the diameter of these impurities is less than a tenth of the gap height. Aggregation takes place in the converging flow field at the channel entrance, but not in the shear field within the slit. It can be suppressed by appropriate stabilization of the primary particles

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“…[21,29,30] Such a curve is shown in Figure 6 where we see the variation of h 0,r as a function of f/f m , where f m is calculated from our model separately for each latex (or the measured value used in the case of the monomodal latices). The effect of particle size on the zero shear viscosity of monodisperse latices and the effect of bimodality of dispersed particles can also be seen in this Figure. Finally, for any bimodal, or more generally a multimodal latex, f m can be estimated from the presented model and then the viscosity can be predicted at any solid content from the master curve.…”

Section: Viscosity Of Bimodal Laticesmentioning

confidence: 99%

“…[9][10][11] If one considers the particular case of a bimodal latex, then at a fixed total volume fraction of polymer (f), the rheology will be influenced by the PSD, and in particular by the ratio of the diameter of the large particles to that of the small ones (l ¼ d l /d s ), as well as the volume fractions of these populations (z ¼ f 1 /f s ). It should also be clear that the amount of surfactant around the particles will influence the PSD to the extent that the thickness of the stabilisation layer will increase the effective volume fraction of the particles.…”

Section: Introductionmentioning

confidence: 99%

Modelling of The Rheological Properties of Bimodal Emulsions

Cassagnau

McKenna

2006

Macromolecular Symposia

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The model of Ouchiyama and Tanaka [1][2][3] was successfully adapted to calculate the maximum packing fraction (f m ) of polymer latexes with varying bimodal particle size distributions based upon rheological measurements performed on its constituent parts. The values of f m calculated from the model can be used to predict the rheological properties of the latices. The model was experimentally validated and used for the prediction the viscosity of studied bimodal latices of known concentration using the master curve of viscosity-reduced volume fraction (h vs. f/f m ).

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Viscosity of bimodal charge-stabilized polymer dispersions

Cited by 17 publications

References 30 publications

Viscosity of Electrostatically Stabilized Dispersions of Monodispersed, Bimodal, and Trimodal Silica Particles

Viscosity of Electrostatically Stabilized Dispersions of Monodispersed, Bimodal, and Trimodal Silica Particles

Clogging of microchannels by nano-particles due to hetero-coagulation in elongational flow

Modelling of The Rheological Properties of Bimodal Emulsions

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