3D-printed polymer composites with acoustically assembled multidimensional filler networks for accelerated heat dissipation

Polymer composites containing thermally conductive fillers show great promise in solving the overheating issue which is critical for electronic devices. Recent successes in developing functional polymer composites rely on the excellent filler property and heavy loading. Yet the intensive filler loading leads to challenges in manufacturing and composite properties. This study reports an alternative method for functional particle-polymer composite design and fabrication: instead of heavy loading, a small amount of filler composes highly concentrated multidimensional network functioning as active paths for heat dissipation in the polymer matrix. A novel 3D printing technique named acoustic field-assisted projection stereolithography realizes the fabrication of such composites. The local filler weight ratio in the network is > 7 times of the feedstock filler loading. With the same feedstock, the patterned composite exhibits >10 times higher efficiency in heat dissipation, compared to the uniform composite. With the same amount of fillers embedded, the patterned composite accelerates the heat dissipation twice than the uniform composite. Moreover, 3D filler network outperforms 2D network, showing that the higher network dimension is conducive to multidirectional heat transfer. With a low filler consumption while higher design flexibility, this new composite material design and manufacturing approach overcomes restriction caused by filler loading.