Abstract:The temperature-responsive silica core-poly(N-isopropylacrylamide) shell (SiO2/PNIPAm) hybrid microspheres were prepared by grafting PNIPAm chains to SiO2 nanoparticles via the combination of reversible addition - fragmentation chain transfer (RAFT) and thiol-ene click chemistry. The SiO2/PNIPAm hybrid microspheres were characterized by FTIR, thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and dynamic laser scattering (DLS). Nearly monodispersed SiO2/PNIPAm hybrid microspheres of 286 nm in average diameters were obtained. The grafting yield and grafting density of PNIPAm brushes on the SiO2 nanoparticles was about 87% and 0.40 chains/nm2. The temperature-responsive of SiO2/PNIPAm hybrid microspheres were investigated by DLS. The hydrodynamic diameters (Dh) of SiO2/PNIPAm hybrid microspheres decreased from about 286 nm to about 268 nm as the temperature of the aqueous medium increased from 25 to 35 oC, the PNIPAm shell thicknesses decreased from about 16 nm to about 7 nm.