Preparation and characterization of thermosensitive polymers grafted onto silica-coated iron oxide nanoparticles

In this study, multifunctional nanoparticles containing thermosensitive polymers grafted onto the surfaces of 6-nm monodisperse Fe3O4 magnetic nanoparticles coated by silica were synthesized using reverse microemulsions and free radical polymerization. The magnetic properties of SiO2/Fe3O4 nanoparticles show superparamagnetic behavior. Thermosensitive PNIPAM (poly(N-isopropylacrylamide)) was then grafted onto the surfaces of SiO2/Fe3O4 nanoparticles, generating thermosensitive and magnetic properties of nanocomposites. The sizes of fabricated nanoparticles with core–shell structure are controlled at about 30 nm and each nanoparticle contains only one monodisperse Fe3O4 core. For thermosensitivity analysis, the phase transition temperatures of multifunctional nanoparticles measured using DSC was at around 34–36 °C. The magnetic characteristics of these multifunctional nanoparticles were also superparamagnetic.

Graphical abstractMultifunctional nanoparticles were synthesized by grafting PNIPAM onto the surfaces of SiO2/Fe3O4 nanoparticles. The physical properties of these nanoparticles show superparamagnetic behavior with thermosensitivity.Figure optionsDownload full-size imageDownload as PowerPoint slide