The core/shell SiOx@polyacrylamide (SiOx@ PAN nanospheres were successfully prepared by the in situ surface-initiated free radical polymerization of acrylamide (AM) from the silica nanoparticles with self-assembled monolayers (SAMs) of N-methyl aniline (NMA) in presence of benzophonone via a precipitation polymerization method under the ultraviolet (UV) irradiation. The conversion of monomer (C%) and the percentage of encapsulating (PE%), calculated from the elemental analyses (EA) results, reached 20.9 and 51.0% after 150 min of UV-irradiation, respectively. It is consistent with the analyses of TGA. Fourier transform infrared (FTIR) analyses also confirmed the formation of the core/shell SiOx@PAM nanospheres. And it was investigated that the silica nanoparticles had been encapsulated with PAM from the X-ray photoelectron spectrometer (XPS) analyses. The analysis results of transmission electron microscope (TEM) showed that the diameters of the SiQ(x)@PAM nanospheres were in the range of 50-200 nm. (c) 2006 Wiley Periodicals, Inc.