Encapsulation Through Mini Emulsion Polymerization

Copyright 2006 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim 

A recent development, where high-shear devices such as ultrasound and high-pressure homogenizers were used to reduce droplet size and the nanoreactor diameter to 30-100 nm, thus allowing the formulation of different types of nanocapsule, forms the main subject of this chapter. 

Based on the principle of miniemulsion, it is now possible to prepare new nanoparticles which could not be created by using heterophase processes. In particular, this includes the encapsulation of different liquid and solid materials, and this topic will form the main content of this chapter. 

This mechanism was used previously to stabilize fluoroalkane droplets by adding the ultrahydrophobe perfluorodimorphineopropane, the results being the production of an effective and stable blood substitute [7]. A variety of molecules can be used as hydrophobes, although they must be chosen such that they add useful properties to the final product for example, the molecule may be a dye, a plasticizer, or a cross-Knker, while for biomedical applications this component might also be a fluorescent marker or a drug. 

In the inverse situation the droplet size throughout the miniemulsification process achieves an equilibrium state (steady-state miniemulsion) this is characterized by a dynamic rate equiKbrium between fusion and fission of the droplets, and can be determined turbidimetricaUy. A high stabihty of the droplets after high- 

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Encapsulation is the process of obtaining small solid nanoparticles, liquid nanodroplets or gas nanobubbles with a polymeric coating. We will give a historic account of some of the early work on encapsulating inorganic pigments and fillers with a polymer through (mini)emulsion polymerization. 

Fig. 4 Representation of encapsulation of inorganic (submicrometer) particles through the layer-by-layer approach (left) or (mini)emulsion polymerization (right)...

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