Impact of (Unconventional) Surfactants in Oil Nanoemulsification

This study provides insights to expand the nanoemulsification domain and produce more concentrated emulsions through a one-pot solvent shifting. The Ouzo effect is a straightforward process for generating nanoparticles, emulsions, or solid dispersions on demand. However, the high dilution of the derived colloidal objects limits the scalability of this process. In this work, we introduce two surfactants not commonly used in conventional emulsions to examine their impact on the solvent shifting method. Both surfactants, a nonionic surfactant and an electrosteric surfactant, broaden the (nano)emulsification window for conventional oils, specifically hexadecane and Miglyol 812. The sizes of the resulting oil nanodroplets cover a wider range, and the corresponding emulsions remain stable for a longer period. Notably, synergistic effects are observed when the two surfactants are used together, allowing for the preparation of nanoemulsions with higher oil contents through solvent shifting.