Drop Detachment from a Micro-Engineered Membrane Surface in a Dynamic Membrane Emulsification Process

Drop size distribution is an important characteristic of emulsions, probably the most crucial one for their use in various applications. Here, a pilot-scale apparatus with a cone-shaped flow geometry is introduced. The plate contains a micro-engineered membrane manufactured from silicon allowing for the production of emulsions with narrow drop size distributions. The process is characterized by producing model emulsions of the oil-in-water type under laminar rheometric flow conditions and by accessing the regime of drop detachment as a function of the wall shear stress applied, by means of high-speed imaging in a separate flow cell. Furthermore, clear evidence is given of the crucial influence of the membrane wetting properties on the emulsification results, by comparing the performance of micro-engineered membranes composed either of silicon, silicon nitride, or nickel, for pore diameters from 1 to 12m, in the flow cell.