Stabilization of O/W emulsion with hydrophilic/hydrophobic clay particles

In this study, a stabilizing behavior of clay in a 40/60 w/w oil-in-water (O/W) emulsion is investigated by macro- and microscopic morphological observations, rheology, and X-ray diffraction measurements. Hydrophilic and hydrophobic clays (Montmorillonites) are tested for stabilization of emulsion. When hydrophilic clay showing interfacial localization is added to the emulsion, emulsion is not stable to phase separation (creaming). With hydrophobic clay, the emulsion shows phase inversion to water-in-oil (W/O) emulsion due to the increase in oil viscosity which results in phase separation of sedimentation. On the other hand, with the mixture of hydrophilic and hydrophobic clays, the emulsion shows a synergistic macroscopic and microscopic stabilization due to the formation of composite structure at the interface by hydrophilic and hydrophobic clays.