A review of multiple Pickering emulsions: Solid stabilization, preparation, particle effect, and application

The emulsions stabilized by solid particles, Pickering emulsion, have excellent stability and are environmentally friendly compared to the emulsions stabilized by surfactants upon most occasions. The physical–chemical properties of emulsion system, such as stimuli responsive, controllable release and mechanical strength can be precisely tuned through the particle properties and preparation process. This review has carried on the target-oriented summary about the recent progress and applications of multiple Pickering emulsions. The unique superiority of Pickering stabilization at liquid–liquid interface is discussed. The particle wettability has been proved to play an important role in emulsions formation and stabilization. How to prepare multiple Pickering emulsions successfully are described based on emulsification process and novel technologies. And the influence of particles on the multiple emulsion properties are analyzed. In addition, we present the applications of multiple emulsions in material preparation, such as microspheres and microcapsules, and its application for reaction process is prospected.