Design of network Al2O3 spheres for significantly enhanced thermal conductivity of polymer composites

It is of great significance to realize high thermal conductivity of polymer composites, which are used in electronic devices. However, traditional polymer composites exhibit limited thermal conductivity due to high interfacial thermal resistance. Herein, network Al2O3 (N-Al2O3) with multidimensional continuous structures is fabricated by a feasible strategy and first used as fillers for phenolic resin (PR), achieving significantly enhanced thermal conductivity of 4.01 Wm−1 K−1, enhanced by 1800% compared with neat matrix. The unique N-Al2O3 is responsible for the excellent thermal conductivity, which contributes to the continuous thermal transfer pathways with decreased interfacial thermal resistance. Additionally, owing to the interpenetrating structure of N-Al2O3 and PR, composites display improved mechanical properties and thermal stability. Dielectric loss tangent of composites decreases with increasing N-Al2O3, which is unusual and desired for thermal interface materials used in electronic devices. Therefore, our strategy offers new guidelines in fabricating high-quality composites for commercial applications.