Preparation and characterization of magnetic hollow PMMA nanospheres via in situ emulsion polymerization

Magnetic hollow polymethyl methacrylate (PMMA) nanospheres were successfully obtained by etching the template of CaCO3 in the core–shell Fe3O4@CaCO3@PMMA nanospheres, which were synthesized via in situ emulsion polymerization in the presence of oleic acid-modified Fe3O4@CaCO3 composite nanoparticles. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements demonstrated that the core–shell Fe3O4@CaCO3@PMMA nanospheres were uniform and possessed narrow size distributions. And a perfect spherical profile of magnetic hollow PMMA nanospheres could be also observed by TEM. Both the Fourier transform infrared (FTIR) spectrometry, high resolution TEM (HRTEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) provided the sufficient evidences for the presence of Fe3O4 in the magnetic hollow PMMA nanospheres. Thermogravimetric analysis (TGA) investigated the composition of the resulting composite nanospheres. Moreover, the magnetic testing experiment could give us a direct proof of the presence of Fe3O4 in magnetic hollow PMMA nanospheres. And the magnetic hollow PMMA nanospheres had a promising future in controlled drug delivery and targeted drug applications.