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Extraction and Characterization of Surfactants from Atmospheric Aerosols
Published on: April 21, 2017
The sponge phase of a mixed surfactant system
A Maldonado1, R Ober, T Gulik-Krzywicki
1Departamento de Física, Universidad de Sonora, Apdo. Postal 1626, 83000 Hermosillo, Sonora, Mexico. maldona@fisica.uson.mx
Journal of Colloid and Interface Science
|February 3, 2007
Summary
This study confirms the existence of the sponge phase in mixed surfactant systems. Increasing charged surfactant concentration maintains the sponge phase structure and allows for geometrical obstruction factor determination.
Area of Science:
- Physical chemistry
- Materials science
- Colloid and surface science
Background:
- The sponge phase is a complex fluidic phase formed by surfactants.
- Understanding its behavior in mixed surfactant systems is crucial for applications.
Purpose of the Study:
- To investigate the existence and structural stability of the sponge phase in a mixed non-ionic/ionic surfactant system (C14DMAO-TTAB-hexanol-brine).
- To explore the impact of increasing charged surfactant concentration on the sponge phase structure.
- To develop a method for determining the geometrical obstruction factor in ionic sponge phases.
Main Methods:
- Small-angle X-ray scattering (SAXS) to analyze structural properties.
- Freeze-fracture electron microscopy (FFEM) for visualizing microstructure.
- Electrical conductivity measurements to probe ion transport and phase behavior.
Main Results:
- The sponge phase exists and preserves its global structure even with increased charged surfactant content at constant bilayer volume fraction.
- A novel method was proposed and validated for calculating the geometrical obstruction factor using conductivity data.
- Lamellar phases within the same system exhibited increased bilayer thickness with higher ionic surfactant concentrations.
Conclusions:
- The mixed surfactant system supports a stable sponge phase whose fundamental structure is resilient to changes in ionic surfactant ratio.
- Electrical conductivity is a viable tool for characterizing ionic sponge phases and determining key geometrical parameters.
- Ionic surfactant addition influences bilayer organization, leading to thickening in lamellar phases.
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