Synergistic effect of spherical Al2O3 particles and BN nanoplates on the thermal transport properties of polymer composites

Efficient heat transport along through-plane direction is one of the primary requisites for thermal interface materials (TIMs) to relieve heat accumulation at the interface between chip and heat sinks. We report enhanced thermal conduction of Al2O3-based polymer composites by surface wetting and texturing of thermally conductive hexagonal boron nitride (h-BN) nanoplatelets with large anisotropy (diameter <500 nm, thickness <30 nm) in morphology and physical properties. The thermally conductive polymer composites are prepared with hybrid fillers of Al2O3 macrobeads and surface modified h-BN nanoplatelets. Here, the clustering or assembly of h-BN nanoplatelets is analyzed based on depletion interaction of colloidal particles. In addition, further addition of minimal amount of SiO2 nanoparticles shows a drastic improvement of thermal transport properties, which is attributed to the depletion interaction between nanoplatelets mediated by spherical nanoparticles. Here, the benefits of surface wetting for thermal management composite materials are illustrated.

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