3D printed polymer nanocomposites with boron nitride nanosheets for enhanced directional thermal transport

Boron nitride nanosheets (BNN) have attracted sustained interest for advanced thermal management applications due to their superior thermal conductivity and electrical insulation. In this work, exfoliated BNN materials were dispersed into polymer matrices for fabricating nanocomposites thin films with tailored directional thermal transport properties. Compared to conventional wet casting approach for fabricating nanocomposite films with predominantly in-plane aligned BNN, masked stereolithography (MSLA) 3D printing was exploited as a versatile fabrication approach to achieve controlled in-plane and cross-plane alignment of BNN within polymer matrices. The results showed that the 3D printed nanocomposite exhibited much improved thermal performance, with significantly enhanced in-plane or cross-plane thermal transport depending on the printing directions. For example, the 3D printed nanocomposite films with 15 wt% BNN loading yielded approximately a 4-fold enhancement in in-plane thermal conductivity via horizontal alignment and faster cross-plane temperature rise in cross-plane alignment. These results highlighted the advantages and unique capabilities of 3D printing fabrication in the development of BNN-derived nanocomposite for directional thermal transport and related thermal management applications.