Related Experiment Video
Updated: Aug 4, 2026
07:46
An Efficient and Flexible Cell Aggregation Method for 3D Spheroid Production
Published on: March 27, 2017
Depletion Interactions Produced by Nonadsorbing Charged and Uncharged Spheroids
Journal of Colloid and Interface Science
|November 10, 2000
Summary
Macromolecule shape significantly impacts depletion attraction between particles. Spheroidal shapes can increase interaction strength, potentially causing flocculation in charged particle dispersions.
Area of Science:
- Colloid and Surface Science
- Physical Chemistry
- Polymer Science
Background:
- Depletion attraction is a key phenomenon in colloidal systems.
- The influence of macromolecule shape on this attraction is not fully understood.
- Previous models often simplified macromolecule geometry.
Purpose of the Study:
- To investigate the effect of macromolecule shape (spheroids) on depletion attraction.
- To develop analytical expressions for uncharged systems.
- To analyze the impact of macromolecule charge and shape on particle dispersion stability.
Main Methods:
- Utilized a modified force-balance model.
- Represented macromolecules as general spheroids (charged or uncharged).
- Developed analytical expressions for large particles and performed scaling analysis.
Main Results:
- Increasing spheroidal aspect ratio decreases attraction at constant number density but increases it at constant volume fraction.
- Prolate spheroids yield stronger attraction than oblate spheroids at constant volume fraction.
- Surface charge enhances attraction range and magnitude, and charged spheroids can induce flocculation.
Conclusions:
- Macromolecule shape is a critical factor in depletion attraction.
- Spheroidal macromolecules offer tunable control over colloidal interactions.
- Understanding these interactions is crucial for stabilizing charged particle dispersions.
More Related Videos
Related Concept Videos
03:13Intermolecular Forces
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen bonds, and dispersion...
03:00Solubility
Solution, Solubility, and Solubility Equilibrium
A solution is a homogeneous mixture composed of a solvent, the major component, and a solute, the minor component. The physical state of a solution—solid, liquid, or gas—is typically the same as that of the solvent. Solute concentrations are often described with qualitative terms such as dilute (of relatively low concentration) and concentrated (of relatively high concentration).
In a solution, the solute particles (molecules, atoms, and/or ions)...
A solution is a homogeneous mixture composed of a solvent, the major component, and a solute, the minor component. The physical state of a solution—solid, liquid, or gas—is typically the same as that of the solvent. Solute concentrations are often described with qualitative terms such as dilute (of relatively low concentration) and concentrated (of relatively high concentration).
In a solution, the solute particles (molecules, atoms, and/or ions)...
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...
01:17Ion Exchange
Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or basic...
01:09Analyte Adsorption and Distribution
In certain chromatographic separations, solutes transfer between the mobile phase and the stationary phase via sorption, which typically refers to the process of adsorption. For many chromatographic systems, the sorption process often depends on the polarity of the compounds—an expression of the overall dipole moment within the molecule. During the separation process, there is competition between the solute and solvent for adsorption to the stationary phase. Highly polar compounds and solvents...
01:29The Colloidal State
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 the...