Three-Dimensional Periodically Ordered Nanohetero Metallic Materials from Self-Assembled Block Copolymer Composites

We report a synthetic route to inorganic nanoheterostructures with tunable size and morphology via self-assembled block copolymer mesophase templates. Two Fe precursors, tricarbonyl(cyclooctatetraene) iron and acetylacetonate iron(III), and one Pt precursor, platinum dimethylcyclooctadiene, were selectively introduced into separate polymer blocks of a block copolymer, polystyrene-b-poly-4-vinylpyridine, and then the block copolymer templates were removed by pyrolysis. Self-assembled inorganic nanoheterostructures (spheres, hexagonal cylinders, and layers of hard magnetic phase FePt in a matrix of soft magnetic phase α-Fe) were produced. The morphology and domain size of the nanoheterostructures could be tailored by controlling the molecular weight and relative block lengths of the block copolymers. The controlled size and morphology of the inorganic nanoheterostructures demonstrate the method’s utility for producing highly functional materials.