Effect of silane-coupling agents on synthesis and character of core-shell SiO2 magnetic microspheres

The core-shell SiO2 magnetic microspheres (MMS) were prepared through sol–gel method. The transmission electron microscope (TEM), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM) were used to characterize the appearance, phase, functional groups on the surface and the magnetic character of the SiO2 MMS. The influence of silane-coupling agents on the preparation of SiO2 MMS was studied and the results show that the selection of silane-coupling agents and the coupling process are important to the preparation of SiO2 MMS. The SiO2 MMS obtained exhibit the excellent super-paramagnetism behavior and keep the good magnetic response.