Related Experiment Video
Updated: Apr 3, 2026
10:56
Confocal Imaging of Confined Quiescent and Flowing Colloid-polymer Mixtures
Published on: May 20, 2014
12.6K
Percolation in suspensions and de Gennes conjectures.
Stany Gallier1, Elisabeth Lemaire2, François Peters2
1SAFRAN-Herakles, Le Bouchet Research Center, 91710 Vert le Petit, France.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|September 19, 2015
Summary
Sheared suspensions form transient particle clusters that exhibit percolation. These findings validate theoretical conjectures and highlight the importance of percolation in suspension physics.
Area of Science:
- Rheology and soft matter physics
- Computational fluid dynamics
Background:
- Dense suspensions exhibit complex flow behaviors between solid and liquid states.
- Shear-induced particle clustering and percolation are hypothesized to influence suspension properties.
- Previous theoretical conjectures on suspension percolation remain experimentally unvalidated.
Purpose of the Study:
- To investigate the formation and characteristics of percolation clusters in sheared noncolloidal suspensions.
- To assess the validity of de Gennes' theoretical conjectures on percolation in suspensions.
- To understand the role of percolation clusters in the rheological behavior of suspensions.
Main Methods:
- Three-dimensional detailed numerical simulations were employed.
- Analysis focused on particle clustering and cluster formation under shear.
- Critical exponents were computed to characterize cluster properties.
Main Results:
- Percolation clusters form in sheared noncolloidal suspensions at a critical volume fraction (0.3-0.4).
- These clusters are linear, transient, and involve a limited number of particles.
- Standard isotropic percolation theory adequately describes the observed clusters.
Conclusions:
- The study validates de Gennes' conjectures on percolation in suspensions.
- Percolation concepts are relevant to understanding suspension physics.
- The impact of percolation clusters on rheology is found to be less significant than previously thought.
Related Concept Videos
01:17Colloids and Suspensions
3.9K
Children at play often make suspensions such as mixtures of mud and water, flour and water, or a suspension of solid pigments in water known as tempera paint. These suspensions are heterogeneous mixtures composed of relatively large particles visible to the naked eye or seen with a magnifying glass. They are cloudy, and the suspended particles settle out after mixing. The suspended particles in a suspension settle out after some time of mixing. The separation of particles from a suspension is...
3.9K
01:09Colloidal precipitates
6.8K
The high insolubility of some precipitates can result in an unfavorable relative supersaturation. This can lead to colloidal particles with a large surface-to-mass ratio, where adsorption is promoted. For instance, in the precipitation of silver chloride, silver ions are adsorbed on the surface of the colloidal particles, forming a primary layer. This layer attracts ions of opposite charge (such as nitrate ions), forming a diffuse secondary layer of adsorbed ions. This electric double layer...
6.8K
03:22Colloids
22.1K
Children at play often make suspensions such as mixtures of mud and water, flour and water, or a suspension of solid pigments in water known as tempera paint. These suspensions are heterogeneous mixtures composed of relatively large particles that are visible to the naked eye or can be seen with a magnifying glass. They are cloudy, and the suspended particles settle out after mixing. On the other hand, a solution is a homogeneous mixture in which no settling occurs and in which the dissolved...
22.1K
01:29The Colloidal State
152
The formation of a colloidal system is exemplified by an aqueous solution containing Cl− ions is introduced to another containing Ag+ ions, resulting in the precipitation of solid AgCl as extremely tiny crystals. Instead of settling out as a filterable precipitate, these crystals remain suspended in the liquid, showcasing a colloidal system.A colloidal system involves colloidal particles within the approximate range of 1 to 1000 nm in at least one dimension, dispersed in a medium called...
152
01:10Types of Coprecipitation
7.0K
Coprecipitation is the contamination of a precipitate by otherwise soluble species and occurs via different processes. In colloidal precipitates, coprecipitation occurs via surface adsorption. For instance, barium sulfate has a primary layer of adsorbed barium ions and a secondary layer of nitrate counterions. This results in contamination of the precipitate by barium nitrate.
Sometimes, ions in a crystal lattice can undergo isomorphous replacement by inclusions of similar charge and size. For...
Sometimes, ions in a crystal lattice can undergo isomorphous replacement by inclusions of similar charge and size. For...
7.0K
01:15Theories of Dissolution: Diffusion Layer Model
2.2K
Dissolution, the process by which drug particles dissolve in a solvent, is explained by the diffusion layer model, a theoretical framework that simulates the absorption of oral drugs and allows us to analyze experimental data.
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
2.2K