Encapsulation by Co-Miniemulsion

In order to increase the amount of encapsulated carbon to 80 wt%, another approach was developed [99] whereby both monomer and carbon black were independently dispersed in water using SDS as a surfactant and subsequently mixed in 

TEM and ultracentrifugation studies showed that this process results in effective encapsulation of the carbon with almost complete yield (Fig. 2.11) only rather small hybrid particles, but no free carbon or empty polymer particles, were found. It must be stated that the hybrid particles with high carbon content do not possess a spherical shape, but rather adopt the typical fractal structure of carbon clusters, coated with a thin (but homogeneous) polymer film. The thickness of the monomer film depends on the amount of monomer, and the exchange of monomer between different surface layers is - as in miniemulsion polymerization -suppressed by the presence of an ultrahydrophobe. 

Magnetic fluids are stable dispersions of ultrafine magnetic particles or encapsulated magnetic particles in an organic or aqueous carrier medium. The stabihza-tion of these particles can be achieved by surfactants which hinder the particles from flocculation or sedimentation. In ideal cases, the particles also keep their stability under the exposition of magnetic fields. 

Other applications of magnetic fluids rely on water as the continuous phase. Kelley [108] produced an aqueous magnetic material suspension by the conversion of iron compounds to magnetic iron oxide in the aqueous medium under controlled 

Polymer-covered magnetic particles can also be produced by the precipitation in situ of magnetic materials in the presence of polymer which acts as a stabiHzer. In this way, magnetic polymer nanoparticles are produced in presence of the water-soluble dextran [110], poly(ethylene imine) [111], poly(vinyl alcohol) [112], poly(ethylene glycol) [113], sodium poly(oxyalkylene di-phosphonates) [114], and amylose starch [115]. 

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