Preparation of Uniform Microcapsules and Microspheres from W/O/W Double Emulsion

Double emulsion is complex system, also called “emulsion in emulsion,” in which the droplets of the dispersed phase contain one or more types of smaller dispersed droplets, especially water-in-oil-in-water (W/O/W) double emulsion shows great potential as compartmentalized system to encapsulate multiple components for protecting their activities. For membrane emulsification, two kinds of methods are developed, direct membrane emulsification and premix membrane emulsification. This chapter introduces the preparation of uniform microcapsules and microspheres from W/O/W double emulsion by direct membrane emulsification. The most often used double-emulsion technique for preparation of microcapsules is double emulsion-solvent evaporation technique. Functional composite polymer microspheres have attracted extensive attention, and have a wide variety of applications, including in medical diagnostics, chemical separation, photonics, and biological probes.