C₁₂E₂ Reverse Micelle: A Molecular Dynamics Study

Molecular dynamics (MD) simulations have been carried out to study the microscopic properties of a reverse micelle of the poly(oxyethylene) surfactant C 12 E 2 in nonpolar environments (decane and vacuum). The simulations reveal that the core water molecules and the oxyethylene headgroups of the surfactants behave similarly in decane and vacuum simulations. However, the surfactant tails of the micelle behave differently in a vacuum. In the absence of the solvent the hydrocarbon tails collapse onto the surface of the core. The core water molecules were observed to be less mobile and interact strongly with the oxyethylene headgroups and form hydrogen-bonded bridged structures with the oxygen atoms of the same surfactant chain. This leads to a very strong preference for gauche C−C bonds in the oxyethylene headgroups of the surfactants.