Synthesis of Magnetic Iron OXIDE CORE-Shell Nanoparticles with Tunable Coating Thickness for Enviromental Remediation

A method to synthesize magnetic iron oxide nanoparticles with a crosslinked polystyrene shell using surface initiated atom transfer radical polymerization (ATRP) is presented. The core-shell magnetic nanoparticles were developed to capture contaminents (e.g., polychlorinated biphenyls, PCBs) from contaminated water sources. First, Fe₃O₄ nanoparticles were prepared by reacting aqueous ferric chlorides with ammonium hydroxide. The initiator for ATRP, 2-bromo-2-methyl propionic acid (BMPA), was then coated onto the surface of the magnetic nanoparticles via ligand exchange. Finally, the BMPA-coated nanoparticles underwent ATRP process with styrene and curcumin multiacrylate (CMA) in organic media using copper and 4,4â??-dinoyl-2,2â??-dipyridil (DNDP) to carry out the controlled/â?livingâ? polymerization. The synthesized core-shell nanoparticles were then washed and stored in dimethysulfoxide (DMSO). Dynamic light scattering (DLS) was used to characterize the size of uncoated and coated nanoparticle as a function of reaction time. Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and X-ray diffraction (XRD) were used to confirm the properties and presence of the polymeric shell. UV-visible spectroscopy was used to evaluate the stability of modified nanoparticles in DMSO solution. Overall, controlled shell thickness of the core-shell nanoparticles was demonstrated as a function of reaction time, obtaining nanoparticles with magnetic properties and shell network components that offer great promise for environmental remediation applications.