Microencapsulation by Miniemulsion Polymerization

For microencapsulation by miniemulsion polymerization, oil can be a monomer and the hydrophobe can be a hquid active agent in the above-mentioned miniemulsion system. The monomer and oil are chosen in such a way that these two components are misdble before the polymerization process. As soon as polymerization takes place, phase separation occurs and at the end of polymerization microcapsules containing active agent are obtained. 

Tiarks et al. have described in detail the theory of droplets composed of binary mixtures in relation to the preparation of polymeric nanocapsules containing HD by miniemulsion polymerization using poly(methyl methacrylate) (PMMA) or PS polymer [37]. First, a miniemulsion of oil phase (monomer -r HD -t initiator) dispersed in aqueous phase and containing an appropriate surfactant is prepared by ultrasonication. The polymerization is initiated by heating the emulsion to 68 °C. When the polymer is formed it separates from the HD phase and, depending on the interfadal tension and spreading coeffidents of monomer/polymer, HD (hydrophobe) and water, capsules with different morphologies are obtained. 

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