Atomistic level molecular dynamics simulation on the solubilization mechanism of aromatic molecules in anionic micelles

Abstract

Molecular dynamics simulation of micelle–organic complex reveals interesting insights into the solubilization and stability of such systems. Various interpretations based on measurement of size, solubilization isotherm, time resolved fluorescence decay, etc., provide qualitative information about solubilization of organic molecules, mostly benzene and alkanols. The present simulation, based on all-atom CHARMM force-field parameters analyzes the solubilization mechanism. It is observed that solubilization of benzene and toluene occurs in the palisade and inner core of the micelle. Polar aromatics such as pyridine and phenol are solubilized in the micelle–water interface and Stern layer. The hydrophobicity, polarity and size of the aromatic molecule influence solubilization. Thermodynamic free energy and entropy change of the system are responsible for deformation in the shape of the micelle and its binding efficiency. The present work helps in selection of surfactant–solute pairs and fundamental understanding of the micellar enhanced ultrafiltration process for removal of toxic organic components from water.