Interfacial Behavior and Adsorption Mechanisms of Sorbitol Polyether Ester Emulsifiers in D-Phase Emulsion Systems:...

D-phase emulsification technology has emerged as an efficient, low-energy emulsification technique. Nonionic emulsifiers are extensively employed in the D-phase emulsification process. Nevertheless, the emulsification mechanism and the relationship between emulsifier structures and their interfacial behavior during D-phase emulsification have been scarcely investigated, which restricts the targeted optimization and application of this technology in the industrial field. In this study, the pseudoternary phase behavior and interfacial adsorption characteristics of sorbitol polyether ester emulsifiers with variations in the numbers of hydrophilic groups (6, 30, and 60) and different types of hydrophobic groups (oleate and isostearate) were studied. Sorbitol polyether-30 tetraoleate (TS 30) exhibited the largest interfacial adsorption capacity (3.27 × 10^-6 mol/m²) and a tendency to arrange orderly at the oil/glycerol interface, in comparison to those containing 6 or 60 hydrophilic groups. Confocal laser scanning microscopy (CLSM) and cryogenic transmission electron microscopy (Cryo-TEM) collectively verified that TS 30 and TIS 30 were capable of stabilizing the O/D phase and generating nanoemulsions with small and uniform droplet sizes. This study can enrich the basic studies on the interfacial mechanism involved in D-phase emulsification, providing theoretical references for D-phase emulsification and offering practical guidance for the rational selection of emulsifiers.