Thermally Conductive 3D-Printed Carbon-Nanotube-Filled Polymer Nanocomposites for Scalable Thermal Management

Thermal transportation in a preferred direction is desirable and important for addressing thermal management issues. With the merits of high thermal conductivity, good chemical stability, and desirable mechanical properties, carbon nanotubes (CNTs) have a great potential for wide applications in heat dissipation devices. The combination of 3D printing and CNTs can enable unlimited possibilities for hierarchically aligned structural programming. We report the formation of through-plane aligned multiwalled CNT (MWCNT)-filled polylactic acid (PLA) nanocomposites by 3D printing. The as-printed vertically (or through-plane) aligned structure demonstrates a through-plane thermal conductivity (k⊥) of ∼0.575 W/(mK) at 20 wt % MWCNT content, which is around 2.64 times that of a horizontally aligned structure (∼0.218 W/(mK)) and around 5.87 times that of neat PLA (∼0.098 W/(mK)) at 35 °C. Infrared thermal imaging performed on 3D-printed MWCNT/PLA heat sink verified the superior performance of the nanocomposite compared to that of the matrix polymer. In this study, we achieved the manufacturing of MWCNT/PLA with a high filler loading and a significant improvement in thermal conductivity simultaneously. This work paves the way to develop 3D-printed carbon filler-reinforced polymer composites for thermal-related applications such as heat sinks or thermal radiators.