Influencing factors of multiple emulsions formed by one-step emulsification

Abstract

In this paper, the influence of the emulsifier structure, emulsifier solubility in oils, and oil polarity on the one-step formation of multiple emulsions was studied. The phase inversion process and the morphology of different types of multiple emulsions were investigated based on electrical conductivity measurements, microscopy, and pseudo-ternary phase diagrams. Emulsifiers with branched alkyl groups and polyethers, which were distributed on both sides of the main chain, or with amphiphilic diblock copolypeptides, can form multiple emulsions because of their strong hydrophilic properties. Hydrophobic emulsifiers with good solubility in oils were also conducive to the formation of one-step multiple emulsions. DC200 and Squalane worked well with the system, indicating that low-polarity oils were beneficial to the formation of one-step multiple emulsions. This study provides recommendations for future investigations and applications in food, pharmaceuticals, and cosmetics, including drug delivery and the encapsulation of hydrophilic active.