Preparation of sulfate- and carboxyl-functionalized magnetite/polystyrene spheres for further deposition of gold nanoparticles

A synthetic method developed for preparation of sulfate- and carboxyl-functionalized magnetite/polystyrene (Fe(3)O(4)/PS) spheres that can be further decorated with gold (Au) nanoparticles is reported. By using emulsifier-free emulsion polymerization based on potassium persulfate (KPS)/methyl acrylic acid (MAA)/water system in the presence of Fe(3)O(4)/PS spheres used as the seeds, PMAA-coated magnetic Fe(3)O(4)-PS spheres were readily obtained. The sulfate group is inherent in KPS for initiating the polymerization of PMAA, and eventually it acts as the reducing agent for the deposition of Au nanoparticles. The carboxyl group, on the other hand, could seemingly contribute to immobilize Au nanoparticles precipitated. The morphologies, magnetic properties, and characteristics of oleate-stabilized Fe(3)O(4) nanoparticles, Fe(3)O(4)/PS spheres, PMAA-coated Fe(3)O(4)/PS spheres, and Au-decorated resultant spheres were respectively studied using transmission electron microscopy, X-ray diffraction, Fourier transform infrared, and superconducting quantum interference device magnetometer.