Synthesis of tri-layer hybrid microspheres with magnetic core and functional polymer shell

Abstract

Tri-layer magnetite/silica/poly(divinylbenzene) (Fe 3O 4/SiO 2/PDVB) core-shell hybrid microspheres were prepared by distillation precipitation polymerization of divinylbenzene (DVB) in the presence of magnetite/3-(methacryloxyl)propyl trimethoxysilane (MPS) modified silica core-shell particles as seeds. The polymerization of DVB was performed in neat acetonitrile with 2,2′-azobisisobutyronitrile (AIBN) as initiator to coat magnetite/MPS-modified silica particles through the capture of DVB oligomers with the aid of vinyl groups on the surface of inorganic seeds in absence of any stabilizer or surfactant. Other magnetite/silica/polymer tri-layer hybrid particles, such as magnetite/silica/poly(ethyleneglycol dimethacrylate) (Fe 3O 4/SiO 2/PEGDMA) and magnetite/silica/poly(ethyleneglycol dimethacrylate- co-methacrylic acid) (Fe 3O 4/SiO 2/P(EGDMA- co-MAA)) with various polarity and functionality, were also prepared by this procedure. Magnetite/silica/poly( N,N′-methylenebisacrylamide- co-methacrylic acid) (Fe 3O 4/SiO 2/P(MBAAm- co-MAA)) were synthesized with unmodified magnetite/silica particles as seeds. The resultant tri-layer hybrid particles were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR), dynamic light scattering, and vibrating sample magnetometer (VSM).