Ilia Vladimirovich Kopanichuk

The sorbitan monooleate (Span 80)/polyoxyethylene sorbitan monooleate (Tween 80) reverse micelles in the water-in-n-decane microemulsion were studied using the molecular dynamics (MD) simulation. The coexistence of the large RMs with the hydrodynamic radii Rh ~10 – 20 nm and small RMs with Rh ~1– 2 nm were previously specified for this system. Models of the both surfactants and decane were based on the united-atom approach to allow us describe the structural properties of the small RMs. The micelles have been self-assembled from an initially homogeneous mixture of surfactant, water and decane molecules. The dependence of the shape of the RMs on the relative content of surfactants has been established. The inner structure of Span 80, Tween 80 and Span 80/Tween 80 RMs was quantitatively described. Tween 80 molecules penetrate the water core while Span 80 molecules locate on the surface of the RM. The obtained data shows that the hydrogen bonds between surfactant molecules form on the surface of the RM and play an important role in the formation of RMs. The water hydrogen bonds density distribution in individual and mixed RMs explain advantages of mixed surfactants system than an individual surfactant.

Computer simulation of pyridine, pyridine-2-ol, and pyridine-2,5-diol solubilization by Span 80–water reverse micelles in n-decane has been performed. All solubilized compounds are polar (their...