A magnetic and thermosensitive poly(N-isopropylacrylamide)(PNIPAM) nanoparticles were prepared by the following procedure. The core-shell composite microparticles were synthesized by precipitating polymerization with Fe3O4 being entrapped with SiO2 as core and cross-linked PNIPAM as shell. Then,the SiO2 core was etched by hydrofluoric acid and magnetic thermosensitive Fe3O4 /PNIPAM particles were formed. It has also been shown that the Fe3O4/PNIPAM nanoparticles are featured by lower critical solution temperature (LCST) at 33.0 ℃ while the temperature varies from 28.0 ℃ to 36.0 ℃. The composite magnetic thermosensitive particles were characterized by XRD,SEM,TEM and FTIR. The synthetic mechanism is also discussed.
