Related Experiment Video
Updated: Aug 1, 2026
09:34
Extraction and Characterization of Surfactants from Atmospheric Aerosols
Published on: April 21, 2017
Transport Properties for Aqueous Sodium Sulfonate Surfactants
Annunziata1, Costantino, D'Errico
1Dipartimento di Chimica, Università di Napoli, Federico II, via Mezzocannone 4, Napoli, 80134, Italy
Journal of Colloid and Interface Science
|July 9, 1999
Summary
Sodium alkylsulfonate diffusion in heavy water reveals critical micelle concentration (CMC) and micelle radii using pulsed field gradient NMR. Surfactant diffusion decreases above CMC due to obstruction and electrostatic effects.
Area of Science:
- Physical Chemistry
- Colloid Science
- Supramolecular Chemistry
Background:
- Sodium alkylsulfonates are surfactants forming micelles in solution.
- Understanding surfactant behavior in aqueous solutions is crucial for various applications.
- Heavy water (D2O) offers unique solvent properties for diffusion studies.
Purpose of the Study:
- To measure intradiffusion coefficients of sodium alkylsulfonates in heavy water.
- To determine the critical micelle concentration (CMC) and micelle radii.
- To investigate the influence of micelles on surfactant diffusion.
Main Methods:
- Pulsed Field Gradient Nuclear Magnetic Resonance (PGSE-NMR) technique.
- Measurement of intradiffusion coefficients at 25°C.
- Solubilization of tetramethylsilane (TMS) to probe micelle diffusion.
Main Results:
- Critical micelle concentration (CMC) determined by slope changes in diffusion trends.
- Micelle radii calculated from micelle intradiffusion coefficients.
- Significant decrease in both monomer and micelle diffusion coefficients above CMC.
Conclusions:
- Observed diffusion decrease attributed to obstruction effects by micelles.
- Electrostatic repulsion between charged micelles enhances the obstruction effect.
- A method for computing Gouy-Chapman layer thickness from diffusion data was proposed.
Related Concept Videos
02:55Solubility of Ionic Compounds
Solubility is the measure of the maximum amount of solute that can be dissolved in a given quantity of solvent at a given temperature and pressure. Solubility is usually measured in molarity (M) or moles per liter (mol/L). A compound is termed soluble if it dissolves in water.
02:19Physical Properties Affecting Solubility
Solutions of Gases in Liquids
As for any solution, the solubility of a gas in a liquid is affected by the attractive intermolecular forces between solute and solvent species. Unlike solid and liquid solutes, however, there is no solute-solute intermolecular attraction to overcome when a gaseous solute dissolves in a liquid solvent since the atoms or molecules comprising a gas are far separated and experience negligible interactions. Consequently, solute-solvent interactions are the sole...
As for any solution, the solubility of a gas in a liquid is affected by the attractive intermolecular forces between solute and solvent species. Unlike solid and liquid solutes, however, there is no solute-solute intermolecular attraction to overcome when a gaseous solute dissolves in a liquid solvent since the atoms or molecules comprising a gas are far separated and experience negligible interactions. Consequently, solute-solvent interactions are the sole...
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)...
01:19Ionic Strength: Effects on Chemical Equilibria
The addition of an inert ionic compound increases the solubility of a sparingly soluble salt. For example, adding potassium nitrate to a saturated solution of calcium sulfate significantly enhances the solubility of calcium sulfate. Le Châtelier's principle cannot predict this shift in the equilibrium. Instead, this could be explained in terms of changes in the effective concentration of the ions in solution in the presence of added inert salt.
In this solution, the primary cation—the calcium...
In this solution, the primary cation—the calcium...
01:27Surface Active Agents
Surfactants, named for their behavior at interfaces, positively adsorb at the interfaces of two phases, reducing interfacial tension. Their versatility as emulsifiers, detergents, and foaming agents stems from this ability. Surfactants, often termed amphiphiles, share the property of amphipathy, with molecules having both hydrophilic and hydrophobic portions. The hydrophilic part is called the head, and the hydrophobic part, including an elongated alkyl substituent, forms the tail.Surfactants...
01:30Micelles
Micelle formation is an intricate process that hinges on the properties of amphiphilic or amphipathic molecules and the conditions of the system in which they are found. Amphiphilic molecules, which have both hydrophilic (water-attracting) and hydrophobic (water-repelling) parts, play a critical role in this process.In aqueous environments, these molecules arrange themselves such that their hydrophilic heads are turned towards the water phase, while their hydrophobic tails are oriented away...