Anisotropically Alignable Magnetic Boron Nitride Platelets Decorated with Iron Oxide Nanoparticles

To effectively utilize the anisotropic characteristics of hexagonal boron nitride (h-BN), we have developed magnetic h-BN hybrid platelets decorated with iron oxide (Fe3O4) nanoparticles, which are used as magnetic carriers for tailoring the anisotropy of h-BN. The as-synthesized Fe3O4-coated h-BN powders can easily move under a relatively low magnetic field. With the aid of iron oxide nanoparticles, h-BN platelets randomly dispersed in an epoxy matrix are successfully reoriented in a direction vertical to the film plane. Moreover, by utilizing the anisotropic characteristics of h-BN platelets, Fe3O4-coated h-BN/epoxy composites exhibit exceptional performance in terms of in-plane thermal conductivity. This result is attributed to an improvement in the heat-transport pathways in composite films due to the anisotropic ordering of thermally conductive h-BN sheets. The Fe3O4-decorated h-BN platelets will be promising candidates for significantly improving the performances of advanced electronic devices that require excellent thermal conductivity and electrical insulation.