Research progress in membrane emulsification technology

In the membrane emulsification process, the dispersed phase permeates through the microporous membrane and distributes in continuous phase under the pressure driving force. In comparison with the conventional methods, such as rotor-stator systems and high- pressure homogenizers, the technique is highly attractive due to its simplicity, potentially lower energy demands, resulting narrow droplet-size distributions and lower wall shear stress. The application of membrane emulsification has extended to various fields, such as the cosmetics, pharmacy and food industries, and some applications of this technology are now being commercially realized. Droplet formation and detachment from membrane pores depend on various process parameters (e.g. trans-membrane pressure, shear stress of the continuous phase acting on the membrane surface), membrane material and structure. Many experimental studies focus on the investigations of process parameters. However, the physical mechanisms of droplet formation are still under investigation so as to better elucidate the roles of operation parameters, and finally model the process.