| A new, facile method for preparing amphiphilic core-shell nanoparticles has recently been developed. Thus, the tert-butyl hydroperoxide-induced graft copolymerization of vinyl monomers from water-soluble bio- and synthetic polymers containing amino groups has been used to prepare a wide variety of nanoparticles. This work focused on the synthesis, characterization, and applications of poly(ethyleneimine)(PEI)-based amphiphilic core-shell nanoparticles. The vinyl monomer used in the initial work was methyl methacrylate (MMA). The effects of the reaction parameters (temperature, time, initiator concentration) were investigated in order to determine the optimal conditions for the graft copolymerizations. Particle size, core diameter and shell thickness were altered by varying the MMA to PEI charge ratio, the pH of the reaction medium and the PEI molecular weight. The core-shell morphology in the nanoparticles produced was clearly identified with TEM. The nanoparticle surface charge and surface functionality were determined using zeta (zeta)-potential measurement and NMR spectroscopy, respectively. Stable nanoparticle latexes were produced with solids contents up to 26%. The effects of salts on the formation of the particles and on the stability of formed particles were also investigated. A new series of nanoparticles was also prepared using a series of different vinyl monomers. The ability of the core-shell nanoparticles to bind target molecules to the core and to the surface was also illustrated. Shell-crosslinked hollow nanoparticles were prepared that formed continuous hollow nanofibers, nanotubes and networks upon isolation. |
