Microchannel Emulsification Technology for Production of Monosized Droplets, Microcapsules, and Microbubbles

An emulsion consists of small, spherical droplets of one of two immiscible liquids in the continuous phase of the other. Emulsion droplets usually have an average diameter in the range of 0.1-100 μm. Monodisperse emulsions are useful for measuring, analyzing, and controlling many of their important physical, physicochemical, and organoleptic properties. Monodisperse-emulsion-based materials (e.g., monodisperse multiple emulsions, microparticles, and microcapsules) have attracted a great deal of interest for various applications, including foods, cosmetics, pharmaceuticals, and chemicals. Emulsions are commonly produced using conventional mechanical emulsification devices. They apply the large, mechanical shear force to disruption of the dispersed phase into smaller droplets. However, the emulsions produced by these devices exhibited considerable polydispersity. Microfabrication technology, which originated from semiconductor technology, makes it possible to precisely fabricate micrometer-sized channels on a microchip. Production of monodisperse emulsions using microdevices has been investigated.