Formation of water‐in‐oil emulsions using dynamic membranes of tunable pore size

Abstract This study presents a method for producing water‐in‐oil emulsions using dynamic membranes composed of hydrophobic glass beads with tunable pore sizes. The effect of premix droplet size, transmembrane pressure, bed height, bead diameter, and continuous‐phase viscosity on the final emulsion droplet size was systematically investigated. Results show that the droplet size after the first pass through the membrane is influenced by premix droplet size and continuous‐phase viscosity, but the dominant factor controlling droplet size is the effective flow velocity. Higher transmembrane pressure and smaller bead diameter increase flow velocity and reduce droplet size, whereas increasing bed height generally decreases flow velocity, leading to larger droplets. Based on these observations, a dimensionless correlation was developed to predict droplet size as a function of Weber number, Newton number, bed height, and viscosity ratio. The correlation accurately captures experimental trends and provides a practical tool for designing dynamic membrane emulsification processes.