Related Experiment Video
Updated: Aug 6, 2026
10:12
Flash NanoPrecipitation for the Encapsulation of Hydrophobic and Hydrophilic Compounds in Polymeric Nanoparticles
Published on: January 7, 2019
Crackling of a coagulating suspension
1P.P.M.D. CNRS UMR 7615 ESPCI, Paris, France.
Summary
Researchers analyzed intermittent dynamics in nonstationary systems, observing crackling periods and arrested dynamics in flocculating suspensions. The duration of these crackling events followed a power-law distribution, revealing key insights into system behavior.
Area of Science:
- Complex systems analysis
- Soft matter physics
- Rheology
Background:
- Nonstationary systems exhibit complex dynamics that are challenging to analyze.
- Understanding particle interactions is crucial for predicting suspension behavior.
- Flocculation in concentrated suspensions involves particle aggregation and altered dynamics.
Purpose of the Study:
- To introduce a novel method for analyzing intermittent dynamics in nonstationary systems.
- To investigate the dynamics of concentrated suspensions during flocculation.
- To characterize the nature of particle motion under changing interaction potentials.
Main Methods:
- Development of a new analytical approach for intermittent dynamics.
- Utilizing diffusing wave spectroscopy to probe suspension dynamics.
- Systematically varying inter-particle repulsion forces.
Main Results:
- Intermittent dynamics were observed in concentrated suspensions as repulsion decreased.
- Dynamics were characterized by rapid 'crackling' periods interspersed with arrested states.
- The duration of crackling periods followed a power-law distribution.
Conclusions:
- The introduced analysis method effectively captures intermittent dynamics.
- Decreasing repulsion interactions trigger crackling and arrested dynamics in suspensions.
- Power-law distributions in crackling duration suggest underlying scaling behaviors in flocculation.
Related Concept Videos
03:22Colloids
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...
01:10Recrystallization: Solid–Solution Equilibria
Recrystallization is a purification technique used to separate impurities from solid compounds. In this technique, no chemical reactions occur. Instead, it exploits physical properties only, specifically, the solubility differences between the desired compound and impurities, either at a single temperature or at different temperatures, and under other selected conditions. The solid-solution equilibrium (solubility equilibrium) of each component in the solution represents a binary phase...
01:17Colloids and Suspensions
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...
01:09Colloidal precipitates
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...
00:52Washing, Drying, and Ignition of Precipitates
After filtration, the precipitate is washed to remove coprecipitated impurities and any remaining mother liquor. Colloidal precipitates, such as silver chloride, are washed with an electrolyte (such as dilute nitric acid) to prevent the peptization of the precipitate. In the case of slightly soluble precipitates, the wash solution contains a common ion to reduce solubility. Lead sulfate, which is slightly soluble in water, is washed with dilute sulfuric acid. Similarly, wash solutions may be...
01:06Coagulation
Colloidal solids are solid particles suspended in solution. They are usually negatively charged, attracting a compact primary layer of positively charged ions, which attract more counterions to form an electrical double layer. Electrostatic repulsion between the charged double layers prevents the particles from colliding, stabilizing the colloids. These solids are often undesirable because they can contain toxins that are difficult to remove. Coagulation is a technique that helps aggregate and...