Abstract

Microencapsulation with miniemulsion polymerization involves the preparation of miniemulsion and subsequent polymerization to form nanoparticles or nanocapsules. Miniemulsion is a special class of emulsion that is stabilized against coalescence by a surfactant and suppressing Ostwald ripening by an osmotic pressure agent, or costabilizer. The miniemulsion is produced by high-energy homogeniza-tion and usually yields stable and narrowly distributed droplets with a size ranging from 50 to 500 nm. Nonpolar droplets can be dispersed into a polar liquid to give a direct miniemulsion, or the oil-in-water miniemulsion, whereas polar droplets dispersed into a nonpolar liquid leads to inverse miniemulsion, or the water-in-oil miniemulsion. During the preparation of miniemulsion, the materials to be encapsulated are normally included in the emulsion droplets, and subsequent polymerization of the system allows for the formation of nanocapsules. The materials that can be encapsulated with this technique may be a hydrophilic or a hydrophobic, a liquid or a solid, an inorganic or an organic material.