In-situ formation of Fe3O4 nanoparticles within the thermo sensitive hairy hybrid particles

Herein we report on the production of composite magnetic yolk-shell particles, where the shell consists of magnetite (Fe3O4) nanoparticle/ polymer bilayer and the colloidal yolk is SiO2 nanoparticles. A simple two-step method was developed for the covalent immobilization of atom-transfer radical polymerization (ATRP) initiators on the SiO2 surface. Well-defined functional polymer-SiO2 hybrids consisted of covalently tethered brushes of N-isopropylacrylamide (NIPAAm) polymer. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) measurements confirmed the nanostructures and the components of the resulting nanoobjects. These stimuli-responsive hybrid gels will have potential applications in biomedical areas, such as tissue engineering and drug delivery. (C) 2008 Elsevier B.V. All rights reserved.