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Updated: Mar 23, 2026
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Self-Nanoemulsification of Healthy Oils to Enhance the Solubility of Lipophilic Drugs
Published on: July 27, 2022
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How to explain microemulsions formed by solvent mixtures without conventional surfactants
Thomas N Zemb1, Michael Klossek2, Tobias Lopian3
1ICSM (Institut de Chimie Séparative de Marcoule), UMR 5257 (Commissariat a l'energie atomique et aux energies alternatives/CNRS/Ecole Nationale Supérieure de Chimie de Montpellier, Université de Montpellier), 30207 Bagnols sur Cèze, France; thomas.zemb@icsm.fr Werner.Kunz@chemie.uni-regensburg.de.
Summary
This study explains how "detergentless" microemulsions form in ternary solutions using ethanol, water, and octanol. A balance between hydration force and entropy drives the stability of these unique surfactant-free systems.
Area of Science:
- Physical Chemistry
- Colloid and Surface Science
- Materials Science
Background:
- Ternary solutions with hydrotropes exhibit unexplained solubilization and enzyme activity.
- Previous research in the 1970s proposed "detergentless" micelles/microemulsions but lacked a general explanation.
- Recent scattering data has revived interest in these systems.
Purpose of the Study:
- To investigate the ethanol-water-octanol system as a model for "detergentless" ternary solutions.
- To propose a general principle explaining the stability of microemulsions in surfactant-free mixtures.
- To elucidate the mechanism behind unexpected solubilization power.
Main Methods:
- Systematic study of ternary mixtures (ethanol-water-octanol).
- Analysis of microstructural evidence using light, X-ray, and neutron scattering with contrast variation.
- Theoretical proposal of a governing principle for microemulsion stability.
Main Results:
- Demonstrated unexpected solubilization power in ternary solutions without conventional surfactants.
- Provided evidence supporting the stability of "detergentless" microemulsions.
- Identified the balance between hydration force and entropy as the key principle.
Conclusions:
- The balance between hydration force and entropy explains microemulsion stability in homogeneous ternary mixtures.
- This principle offers a general explanation for "detergentless" solubilization phenomena.
- Reopens the debate on the fundamental mechanisms governing these complex fluid systems.
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