Role of liquid crystal in the emulsification of a gel emulsion with high internal phase fraction

A gel emulsion with high internal oil phase volume fraction was formed via an inversion process induced by a water–oil ratio change. The process involved the formation of intermediate multiple emulsions prior to inversion. The multiple emulsions contain a liquid crystal formed by the surfactant with water; this was both predicted by the equilibrium phase diagram as well as observed using polarization microscopy. These multiple emulsions were more stable compared to alternative multiple emulsions prepared in the same way with a surfactant that does not form liquid crystals. While the formation of a stable intermediate multiple emulsion may not be a necessary condition for the inversion to occur, the transitional presence of a liquid crystal proved to be a significant factor in the stabilization of the intermediate multiple emulsions. The resulting gel emulsion contained a small fraction of the liquid crystal according to the phase diagram, and it exhibited excellent stability.

Graphical abstractEmulsion phase inversion from an oil-continuous simple emulsion to an oil-dispersed gel emulsion; the process involves an intermediate multiple emulsion stabilized by a liquid crystal.Figure optionsDownload full-size imageDownload as PowerPoint slide