Magnetic polymer nanospheres with high and uniform magnetite content

Magnetic polymer nanospheres with high and uniform magnetite content were synthesized using a new process based on miniemulsion polymerization, where a stable water-based dispersion of sodium dodecyl sulfate (SDS)/oleic acid bilayer coated magnetite aggregates was first synthesized and mixed with monomer styrene miniemulsion. Then another miniemulsification was performed for the full encapsulation of magnetite into monomer droplets. Subsequent polymerization generated magnetic polymer nanospheres. Extensive characterization of magnetic polymer particles by transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA) and Vibrating Sample Magnetometer (VSM) showed that up to 40 wt% of 8 nm superparamagnetic magnetite particles could be uniformly encapsulated into polystyrene nanospheres with an average diameter of 80 nm.