Monodispersed hollow polymer/iron eutectic nanospheres

Oleic acid capped Fe3O4 nanoparticles with a size range of 8-15 nm were prepared by a typical reduction method. Double bonds in the oleic acid molecules were activated and further grafted with methyl methacrylate (MMA) and hydroxyethyl acrylate (HEA) in butyl acetate to obtain acrylate copolymer-coated Fe3O4 nanoparticles. Hexamethylene diisocyanate (HDI) was used as the cross-linking agent to immobilize the surface structure of the nanoparticles. Fe3O4 templates were then disposed of with excessive concentrated HCl solution, and monodispersed ultra-fine and an ultra-light hollow polymer/iron eutectic system with a size range of 18-30 nm was thus obtained. The molecular structures, crystal information, thermal properties, and morphology of the prepared nano-particles were characterized. The results showed that the hollow nanoparticles were composed of an amorphous outer layer and a crystalline inner layer, and that the outer layer and the inner layer mainly consisted of acrylate copolymers and ordered iron oxide atoms, respectively. The cross-linked macromolecular architectures and the chemical bond between Fe atoms and polymeric chains are the main driving force to form such a hollow eutectic system that has never been reported previously. The preparation method reported in this paper firstly develops a route to synthesize hollow polymer/metal eutectic materials, and these hollow nanoparticles have large potential application in the fields of nanoreactors and catalysts.