Unusual Function of Modified Polyolefins for Manipulating Magnetic Nanostructures

The unusual function of a long known plastic additive in industry, polypropylene-graft-maleic anhydride (PP-g-MA), is reviewed for serving as a polymeric surfactant to synthesize and stabilize magnetic nanoparticles (NPs) with tunable morphology and crystalline structure. The synthesis route employs a solution-based, one-pot, bottom-up method. Specifically, magnetic NPs were synthesized through thermo-decomposing organo-metallic precursors [i.e., Fe(CO)(5) or Co-2(CO)(8)] in the presence of PP-g-MA in solvent xylene. By simply changing the backbone length/concentration of PP-g-MA, different morphologies (monodispersed hollow vs. chain-like solid, or chain-like vs. monodispersed polyhedral-shaped NPs) and crystalline structures [alpha- vs. gamma-phase for Fe2O3 NPs, or face-centered cubic (fcc)-vs. epsilon-phase for Co NPs] can be controlled simultaneously. In addition, for the chain-like Fe2O3 NPs, a different chain diameter and building block morphology can be controlled by only varying the molecular weight of PP-g-MA.