Magnetic field-induced enhancement of thermal conductivities in polymer composites by linear clustering of spherical particles

We developed linearly linked spherical fillers in polymer composites with incorporating Al2O3-Fe3O4 hybrid particles under a magnetic field to form thermal networks for high thermal conductivity. The Al2O3-Fe3O4 hybrid particles were prepared by a simple precipitation method and their magnetic properties were characterized with magnetic hysteresis. The Al2O3-Fe3O4 hybrid particles were well aligned through direction of magnetic field as confirmed by microscopic observation. The polymer composites obtained with Al2O3-Fe3O4 hybrid particles possessed high thermal conductivity in a parallel magnetic alignment direction at low filler loading, which is more than 240% outperformed the composites with randomly dispersed fillers.