Modeling micelle formation and interfacial properties with iSAFT classical density functional theory.

Area of Science:

• Physical Chemistry
• Colloid and Surface Science
• Computational Chemistry

Background:

• Surfactants are crucial in numerous applications, reducing interfacial tension between different phases.
• Understanding the relationship between surfactant molecular structure and properties is vital for optimizing industrial and commercial uses.
• Current models often lack explicit inclusion of hydrogen bonding, a key interaction in surfactant systems.

Purpose of the Study:

• To investigate the impact of surfactant architecture on micelle formation and interfacial behavior.
• To apply a classical density functional theory, specifically interfacial statistical associating fluid theory, to model these phenomena.
• To explicitly include hydrogen bonding in the theoretical framework.

Main Methods:

• Utilizing interfacial statistical associating fluid theory, a classical density functional theory.
• Modeling nonionic surfactant/water/oil systems with explicit inclusion of hydrogen bonding.
• Minimizing system free energy by optimizing hydrophobic and hydrophilic interactions.

Main Results:

• The theory successfully predicts micellar structure and interfacial properties.
• It qualitatively agrees with experimental data regarding critical micelle concentration and aggregation number.
• The model was extended to study swollen and reverse swollen micelles, relevant for microemulsion formation.

Conclusions:

• Interfacial statistical associating fluid theory provides a valuable framework for understanding surfactant behavior based on molecular structure.
• The explicit inclusion of hydrogen bonding enhances the model's predictive power for surfactant/water systems.
• This theoretical approach aids in comprehending the formation of complex structures like microemulsions.