Pickering emulsions: Microgels as alternative surfactants

Abstract

Microgels stand out as compelling alternatives to traditional emulsifiers in Pickering emulsions, owing to their unique deformability and responsiveness, distinguishing them from rigid particles and conventional surfactants. In this review, we provide an overview of recent advancements and breakthroughs in microgel synthesis and the stabilization of Pickering emulsions using microgels. Additionally, we discuss the underlying stabilization mechanisms of microgel-stabilized emulsions, elucidating the influencing factors such as microgel properties, environmental conditions, and interfacial structures that significantly impact emulsion stability. Given these recent achievements, we summarize and highlight the promising applications associated with diverse Pickering emulsion systems stabilized by tailored microgels, including interfacial catalysis, functional foods, vaccine adjuvants, stimuli-responsive colloidosomes, and droplet manipulation. Conclusively, we identify the existing research gaps in microgel studies and propose future directions, emphasizing the need for the rational design of microgels, comprehensive mechanism studies of microgel-stabilized emulsions, and the formation of next-generation Pickering emulsions.