Preparation of monolithic superparamagnetic nanoparticle–polymer composites using a polymerizable acetylacetonate and magnetite nanoparticles

The formation of nanoparticle-polymer composites that can be processed by injection molding from superparamagnetic magnetite (Fe3O4) nanoparticles (MNPs) and the polymerizable molecule styryl acetylacetonate (stacac) is described. The best composites were created by first synthesizing MNPs in the presence of a surfactant followed by replacement with an excess of stacac monomer in a surfactant exchange reaction. Polymerization of the stacac–MNP mixture produced a dense packing of nanoparticles within a polymer matrix, resulting in a magnetic, monolithic material that was characterized with a combination of transmission electron microscopy (TEM), Fourier transform infrared absorption spectroscopy (FTIR), powder X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The material exhibited superparamagnetic properties similar to pure MNP samples, albeit with a lower total magnetic saturation. An advantage of this polymer-based composite material is its ability to be processed with methods such as mold-casting or microfluidics into a variety of 3-dimensional structures (e.g., toroids) for different electronics applications.