Population-balance description of shear-induced clustering, gelation and suspension viscosity in sheared DLVO colloids

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Autori principali: Lattuada, M., Zaccone, A., Wu, H., Morbidelli, M.
Natura: Preprint
Pubblicazione: 2016
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author Lattuada, M.
Zaccone, A.
Wu, H.
Morbidelli, M.
author_facet Lattuada, M.
Zaccone, A.
Wu, H.
Morbidelli, M.
contents Application of shear flow to charge-stabilized aqueous colloidal suspensions is ubiquitous in industrial applications and as a means to achieve controlled field-induced assembly of nanoparticles. Yet, applying shear flow to a charge-stabilized colloidal suspension, which is initially monodisperse and in quasi-equilibrium leads to non-trivial clustering phenomena (and sometimes to a gelation transition), dominated by the complex interplay between DLVO interactions and shear flow. The quantitative understanding of these strongly nonequilibrium phenomena is still far from being complete. By taking advantage of a recent shear-induced aggregation rate theory developed in our group, we present here a systematic numerical study, based on the governing master kinetic equation (population-balance) for the shear-induced clustering and breakup of colloids exposed to shear flow. In the presence of sufficiently stable particles, the clustering kinetics is characterized by an initial very slow growth, controlled by repulsion. During this regime, particles are slowly aggregating to form clusters, the reactivity of which increases along with their size growth. When their size reaches a critical threshold, a very rapid, explosive-like growth follows, where shear forces are able to overcome the energy barrier between particles. This stage terminates when a dynamic balance between shear-induced aggregation and cluster breakage is reached. It is also observed that these systems are characterized by a cluster mass distribution that for a long time presents a well-defined bimodality. The model predictions are quantitatively in excellent agreement with available experimental data, showing how the theoretical picture is able to quantitatively account for the underlying nonequilibrum physics.
format Preprint
id arxiv_https___arxiv_org_abs_1605_07376
institution arXiv
publishDate 2016
record_format arxiv
spellingShingle Population-balance description of shear-induced clustering, gelation and suspension viscosity in sheared DLVO colloids
Lattuada, M.
Zaccone, A.
Wu, H.
Morbidelli, M.
Soft Condensed Matter
Statistical Mechanics
Application of shear flow to charge-stabilized aqueous colloidal suspensions is ubiquitous in industrial applications and as a means to achieve controlled field-induced assembly of nanoparticles. Yet, applying shear flow to a charge-stabilized colloidal suspension, which is initially monodisperse and in quasi-equilibrium leads to non-trivial clustering phenomena (and sometimes to a gelation transition), dominated by the complex interplay between DLVO interactions and shear flow. The quantitative understanding of these strongly nonequilibrium phenomena is still far from being complete. By taking advantage of a recent shear-induced aggregation rate theory developed in our group, we present here a systematic numerical study, based on the governing master kinetic equation (population-balance) for the shear-induced clustering and breakup of colloids exposed to shear flow. In the presence of sufficiently stable particles, the clustering kinetics is characterized by an initial very slow growth, controlled by repulsion. During this regime, particles are slowly aggregating to form clusters, the reactivity of which increases along with their size growth. When their size reaches a critical threshold, a very rapid, explosive-like growth follows, where shear forces are able to overcome the energy barrier between particles. This stage terminates when a dynamic balance between shear-induced aggregation and cluster breakage is reached. It is also observed that these systems are characterized by a cluster mass distribution that for a long time presents a well-defined bimodality. The model predictions are quantitatively in excellent agreement with available experimental data, showing how the theoretical picture is able to quantitatively account for the underlying nonequilibrum physics.
title Population-balance description of shear-induced clustering, gelation and suspension viscosity in sheared DLVO colloids
topic Soft Condensed Matter
Statistical Mechanics
url https://arxiv.org/abs/1605.07376