Enhancing the thermal conductivities of aluminum nitride‐ polydimethylsiloxane composites via tailoring of thermal losses in filler networks
Xiaoxiang He, Dan Ou, Ying Ma, Shuying Wu, Ying Chen, Yue Luo, Daming Wu
Abstract
Abstract Traditional methods to overcome the challenges associated with the low thermal conductivities (TCs) of polymer composites range from constructing a continuous filler network to minimizing interface resistance. However, the improvement in the TCs of polymer composites is still limited. A key reason is that the polymer among the filler gaps causes high thermal losses and induces thermal resistance for phonons, as the filler network formed by conventional methods is not compact. Herein, a novel forced compression method, induced by compressing the thicknesses of samples to less than their critical thicknesses in a confined space, was applied to construct a robust network to significantly improve the TCs of polymer composites. Aluminum nitride (AlN) ranging from 0 to 54 wt% was added into polydimethylsiloxane (PDMS) to prepare composites using this method. The enhancement in the TCs of AlN/PDMS composites included several considerations: high compression ratio and filler content both led to a small gap between the fillers in the filler network; the improvement in TC was significantly higher, especially at low filler contents, which simultaneously ensured the mechanical properties of polymer composites. Owing to the gap‐cut behavior, the TC was enhanced to 2.667 W/(mK) at 54 wt% of AlN, which was significantly higher than those in the literature results. The AlN/PDMS sample was then utilized as a heat spreader to decrease the temperature of heat source. The temperature dropped 14.42°C more than pure PDMS sheet. This novel compression process provides a facile approach to prepare light‐weight polymer composites with high TCs.