Vitrimer-Assisted Construction of Boron Nitride Vertically Aligned Nacre-mimetic Composites for Highly Thermally Conductive Thermal Interface Materials

Modern electronic equipment with high integration and power consumption levels urges for more effective thermal interface materials (TIMs) to tackle its increasingly severe cooling issues. To effectively transfer the heat generated by electronic components to the radiator, the TIM is supposed to have a high through-plane thermal conductivity (λ⊥); however, achieving that proved devilishly challenging. Herein, inspired by the structure of the natural shell nacre and based on the construction of a cis-polybutadiene (BR) vitrimer network with reversible B–O bonds, the nacre-mimetic microstructure with vertically aligned hexagonal boron nitride (BN) was rationally designed and fabricated. Combining the hot-pressed orientation with the stacking-welding method, the vertically aligned BN/BR composite (VAC) was obtained by longitudinal slicing, and the designed microstructure with intense orientation was verified by scanning electron microscopy and small-angle X-ray scattering. As a result, the VAC reached an unprecedented λ⊥ of 14.1 W·m–1·K–1 as the BN content was 52 vol %, and the running chip temperature was greatly reduced compared with that of commercial TIM. Besides the superior thermal conductivity, the BN/BR composite has excellent electrical insulation and flame resistance. It is believed that the simple fabrication and extendibility of the biomimetic composites pave a new way for the design and preparation of high-performance TIMs.