Related Experiment Video
Updated: May 28, 2026
13:15
Quantitative and Qualitative Examination of Particle-particle Interactions Using Colloidal Probe Nanoscopy
Published on: July 18, 2014
Interaction forces between colloidal particles in a solution of like-charged, adsorbing nanoparticles
1Virginia Tech, M/C 0211, Department of Chemical Engineering, Blacksburg, VA 24061, USA.
Journal of Colloid and Interface Science
|October 11, 2011
Summary
Highly charged nanoparticles adsorb to microparticles and substrates, altering forces. Depending on concentration, these nanoparticles can stabilize or destabilize colloidal dispersions, unlike non-adsorbing systems.
Area of Science:
- Colloid and Surface Science
- Nanotechnology
- Physical Chemistry
Background:
- Understanding interparticle forces is crucial for controlling colloidal system behavior.
- Nanoparticle adsorption significantly influences macroscopic forces between larger particles.
Purpose of the Study:
- To investigate the effect of adsorbing, highly charged nanoparticles on the force profile between a weakly charged microparticle and a substrate.
- To compare the behavior of adsorbing nanoparticles with non-adsorbing systems.
Main Methods:
- Colloidal probe atomic force microscopy (CP-AFM) was used to measure forces.
- Experiments involved a 5 μm glass microparticle, a glass substrate, and varying concentrations of charged nanoparticles in aqueous solution.
Main Results:
- At low nanoparticle concentrations, adsorption increased electrostatic repulsion.
- At higher concentrations, nanoparticle adsorption induced depletion attraction and then structural forces.
- Adsorbing nanoparticles exhibited different force profiles compared to non-adsorbing systems.
Conclusions:
- Concentration-dependent nanoparticle adsorption can either stabilize or destabilize colloidal dispersions.
- The findings highlight the complex interplay between adsorption, electrostatic, depletion, and structural forces.
- This study offers insights into controlling colloidal assembly and stability through nanoparticle engineering.
Related Concept Videos
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...
01:29The 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...
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...
01:06Coagulation
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...
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)...
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...