Tween-80 on Water/Oil Interface: Structure and Interfacial Tension by Molecular Dynamics Simulations.

Area of Science:

• Chemical Engineering
• Materials Science
• Physical Chemistry

Background:

• Surfactants are crucial in the chemical industry, reducing interfacial tension for emulsion formation and stability.
• Traditional molecular dynamics simulations are limited by system size and timescale constraints for surfactant systems.

Purpose of the Study:

• To develop a coarse-grained model for polysorbate 80 (Tween-80).
• To evaluate the influence of the ethylene oxide chain on water/Tween-80/decane system properties.
• To validate the model's ability to reproduce experimental observations.

Main Methods:

• Development of a coarse-grained model for Tween-80.
• Molecular simulations of the water/Tween-80/decane system.
• Free energy calculations to determine partition coefficients.

Main Results:

• The coarse-grained model successfully reproduced the decrease in interfacial tension with increasing surfactant concentration.
• Observed changes in surfactant orientation at the interface, indicating a preferential adsorption layer.
• Free energy calculations confirmed a higher affinity of Tween-80 for the water phase.

Conclusions:

• The proposed coarse-grained model is effective for simulating Tween-80 behavior.
• The model provides insights into the role of ethylene oxide chains in surfactant performance.
• Simulation results align with expected surfactant behavior at interfaces.