Multiscale molecular dynamics simulation study of polyoxyethylated alcohols self-assembly in emulsion systems

Abstract

Although nonionic surfactants have been widely employed as emulsifiers, their self-assembly behaviors in emulsion systems are not well understood. Herein, we report a multiscale molecular dynamics simulation study on the nonionic surfactant aggregations in alcohol ethoxylate (AEO)/water/octane/hexanol quaternary emulsion systems. By systematically examining the effects of chain length, degree of branching in surfactants and the addition of co-surfactants, we find that the stability of self-assembled emulsions is majorly affected by the hydrophilic chain length and chain distribution at the oil-water interfaces. The presence of branch chains in surfactants can promote the self-assembly. Moreover, the addition of co-surfactants benefits the formation of interface films and facilitates the formation of micro-emulsions. By unraveling the self-assembly mechanism of nonionic surfactants in emulsion systems from a multiscale perspective, this study provides fundamental insights towards the preparation and applications of nonionic-surfactant-based emulsions.