Toward Three‐Dimensional Printed Thermal Conductive Polymeric Composites Using a Binary‐Composite Hybrid Based on Boron Nitride Nanoparticles and Micro‐Diamonds

Thermally conductive polymeric composites are promising for heat management in microelectronic devices. This work presents a binary‐hybrid composite of boron nitride (BN) nanoparticles and micro‐diamond (D) fillers in an elastomeric polyurethane (PU) matrix which can be three‐ dimensionally printed to produce a highly flexible and self‐supporting structure. The research shows that a combination of 16.7 wt% BN and 16.7 wt% D results in a robust network within the polymer matrix to improve the tensile modulus more than nine times with respect to neat PU. Significantly, the hybrid matrix enhances the thermal conductivity by more than two times when compared to neat PU. The enhancement in mechanical, and thermal features make this three‐dimensional printable multiscale hybrid composite suitable for flexible and stretchable microelectronic applications.