Polymeric nanoparticles encapsulation miniemulsion polymerization

Bouanani F, Bendedouch D, Hemery P, et al. (2008) Encapsulation of montmorillonite in nanoparticles by miniemulsion polymerization. Colloid Surf A Physicochem Eng Asp... 

FIGURE 17.2 Encapsulation of nanoparticles with miniemulsion polymerization using a cosonication. 

Costoyas, A., Ramos, J., and Forcada, (. (2009) Encapsulation of silica nanoparticles by miniemulsion polymerization. Journal of Polymer Science Part A Polymer Chemistry, 47 (3), 935—948. 

Forcada J, Ramos J. Encapsulation of inorganic nanoparticles by miniemulsion polymerization. In Mittal V, editor. Miniemulsion polymerization technology. Hoboken, NJ, USA John Wiley Sons, Inc 2010. p. 71-96. 

Also aiming at biomedical applications are nanoscaled hydrogels, prepared in inverse miniemulsion. In crosslinked poly(oligo(ethylene glycol) monomethyl ether methacrylate) (POEOMA) nanogels hydrophilic dyes as the polymeric dye (rhodamine isothiocyanate (RITC) dextran) [41], rhodamine in combination with the drug doxorubicin [42] or gold nanoparticles with bovine serum albumin [43] could be encapsulated. 

In addition to molecularly distributed compounds, the material can also be encapsulated as aggregate, crystal, etc., as is the case for the encapsulation of pigments and, for thermally labile azo-components, photoinitiators, and highly fluorescent quantum dots in polymeric nanoparticles by using the miniemulsion process. 

Fig. 11 (a) Encapsulation of insoluble material black) in miniemulsion. The hydropbobic or hydrophobized insoluble material is dispersed in the monomer phase. This dispersion is subsequently homogenized forming droplets in aqueous surfactant solution, (b) By polymerization, composite nanopeirticles tire generated in the cosonication process the monomer miniemulsion and a dispersion of the hydrophobic or hydrophobized insoluble materials are prepared septirately in tm aqueous phase and mixed together followed by a sonication step leading to an encapsulation of the insoluble material in the monomer droplets. The hybrid droplets are subsequently polymerized in Older to obtain the hybrid nanoparticles... 

Joumaa N, Toussay P, Lansalot M, et al. (2007) Surface modification of iron oxide nanoparticles by a phosphate-based macromonomer and further encapsulation into submicrometer polystyrene particles by miniemulsion polymerization. J Polym Sci Part A Polym Chem 46 327-340... 

Faridi-Majidi R, Sharifi-Sanjani N, Agend F (2006) Encapsulation of magnetic nanoparticles with polystyrene via emulsifier-free miniemulsion polymerization. Thin Solid Films 515 368-374... 

Faridi-Majidi R, Sharifi-Sanjani N (2007) Emulsifier-free miniemulsion polymerization of styrene and the investigation of encapsulation of nanoparticles with polystyrene via this procedure using an anionic initiator. J Appl Polym Sci 105 1244-1250... 

In Chapter 1, Landfester and Weiss outline details of miniemulsion polymerization for the encapsulation of a range of materials such as dyes, pigments, fragrances, photo-initiators, drugs, nanoparticles and biomolecules (DNA) in polymeric nanoparticles. The preparation of nanoparticles with new properties is also presented. 

Hydrophilic materials can be encapsulated with the inverse minianulsions by using interfacial polymerization such as polyaddition and polycondensation, radical, or anionic polymerization. Crespy et al. reported that silver nitrate was encapsulated and subsequently reduced to give silver nanoparticles inside the nanocapsules. The miniemulsions were prepared by anulsilying a solution of amines or alcohols in a polar solvent with cyclohexane as the nonpolar continuous phase. The addition of suitable hydrophobic diisocyanate or diisothiocyanate monomers to the continuous phase allows the polycondensation or the cross-linking reactions to occur at the interface of the droplets. By using different monomers, polyurea, polythiourea, or polyurethane nanocapsules can be formed. The waU thickness of the capsules can be directly tuned by the quantity of the reactants. The nature of the monomers and the continuous phase are the critical factors for the formation of the hollow capsules, which is explained by the interfacial properties of the systan. The resulting polymer nanocapsules could be subsequently dispersed in water. 

Other inorganic nanoparticles have been encapsulated with miniemulsion polymerization, and a hydrophobilizing agent was used to render the particles hydrophobic prior to minianulsification. For example, calcium carbonate was pretreated with stearic acid prior to being dispersed into the monomer phase. Alumina and magnetite were pretreated with oleic acid, laponite was pretreated with a cetyltrimethylammonium bromide, and silica was pretreated with cetyltrimethyl-ammonium chloride" or methacryloxy(propyl)trimethoxysilane. ... 

The miniemulsion process is also very suitable for the preparation of hybrid latex particles. One can have the inorganic particles already present in the droplets, then the polymerization reaction results in encapsulated nanoparticles (see [33]). 

Ramfrez et al. encapsulated double-layer (oleic acid and SDS) surfactant-coated magnetite into polystyrene particles by miniemulsion polymerization [171]. In the three-step process, oleic-acid-coated magnetite and oleic acid/SDS double-coated magnetite were prepared in the first and second step, respectively. The third step consists of the preparation of a miniemulsion by stirring 1 h for pre-emulsification, followed by ultrasonication for 2 min using St as monomer with hexadecane and SDS in water. The encapsulation of magnetite was accomplished by cosonication of an St miniemulsion and SDS-stabilized magnetite nanoparticles. The polymerization was initiated by KPS at 80°C. 

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