The Structure and Thermodynamic Stability of Reverse Micelles in Dry AOT/Alkane Mixtures

TL;DR

This study uses Monte Carlo simulations to reveal that dry sodium AOT reverse micelles form charge-ordered polyhedral shells, suggesting they would be insoluble in nonpolar solvents if water were fully removed.

Contribution

It provides the first detailed simulation-based insight into the structure and stability of dry AOT reverse micelles without water.

Findings

Reverse micelles are charge-ordered polyhedral shells.

The stabilizing energy is significantly large, overshadowing entropy effects.

Dry AOT would be insoluble in nonpolar solvents if water is removed.

Abstract

Monte Carlo simulation studies of reverse micelles of an anionic surfactant, sodium AOT, in a non-polar solvent provide strong evidence that, in the absence of water, these clusters are charge ordered polyhedral shells. The stabilizing energy of these clusters is so large that the entropy of mixing is, in comparison, inconsequential and we predict that, if all waters of hydration could be removed (something not yet accomplished for the sodium salt) then AOT would be insoluble in nonpolar solvents.