(256f) Controlled Assembly of Hybrid Organic/Magnetic Nanoparticles – From Emulsion Droplet Solvent Evaporation to Electrospray

Magnetic nanoparticles with diameters of 5-20 nm exhbiting superparamagnetism, find applications in diverse areas such as magnetic imaging, magnetic separation and drug delivery. In many cases, it is preferable to use magnetic nanoparticle clusters of sizes ~100 nm which retain the superparamagnetic properties of the individual nanoparticles, but have superior magnetic properties when in an applied magnetic field. To this end, we have used solvent evaporation of nanoparticle-containing emulsion droplets to synthesize magnetic spheres and polymer beads coated asymmetrically with the nanoparticles. This approach has been extended using electrospray to make these composite materials, which has the potential to generate nanoparticle clusters (symmetric and asymmetric Janus structures) with narrow size distributions. The structures of the clusters were probed using TEM, SEM, and DLS, and a mechanism for the formation of the nanoclusters is proposed.