Microfluidic Approaches to Pickering Emulsions and Foams: Strategies, Challenges, and Promising Applications

Particle-stabilized emulsions and foams, commonly referred to as Pickering emulsions and foams, offer superior stability and greater functional versatility compared to their conventional polymer- or surfactant-stabilized counterparts, bestowing them with unique features. However, the understanding of particle adsorption dynamics, particle-droplet (or particle-bubble), and interdroplet (or interbubble) interactions during large-scale emulsification remains limited, hindering full exploitation of their potential. In recent years, on-chip microfluidic techniques have provided an effective experimental platform to precisely design and produce Pickering emulsions, and perform systematic analyses with regards to their formation, stability, and dynamics. This review examines recent microfluidic advances in the production and analysis of Pickering emulsions and foams. The discussion focuses on their underlying working principles and classification of the current methods based on the mechanisms by which particles are loaded onto interfaces. The review concludes with a critical evaluation of the advantages, limitations, and emerging applications of microfluidic strategies in this field. Looking ahead, this review highlights how the integration of microfluidics with advanced materials science and analytical tools is expected to open new opportunities for designing functional interfacial systems, enabling process scale-up, and translating Pickering systems into practical applications.