Preparation and Characterization of Cycloalkanol/Water Emulsion Using -Cyclodextrin as an Emulsifier

We examined the preparation and characterization of cycloalkanol/water emulsions using -cyclodextrin (-CD) as an emulsifier. Emulsions were prepared by mixing -CD, cycloalkanol, and water using a vortex mixer. The mechanism of emulsification was investigated with some physicochemical techniques. From phase diagrams of cycloalkanol/-CD/water systems, the emulsion phase extended as the carbon number of cycloalkanols increased. Furthermore, it was thought that the coexistence of precipitated cycloalkanol/-CD complexes were necessary for formation of the emulsion. However, the precipitated complexes did not have surface activity. From observation using a polarized light microscope, it was suggested that the precipitated complexes were formed at the oil-water interface and supplied to the continuous phase. We concluded that cycloalkanol/water emulsions using -CD were stabilized by precipitated complexes that exist on the droplet surface and the continuous phase, and these emulsions were a type of Pickering emulsion.