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

Modern electronic equipment with high integration andpower consumptionlevels urges for more effective thermal interface materials (TIMs)to tackle its increasingly severe cooling issues. To effectively transferthe heat generated by electronic components to the radiator, the TIMis supposed to have a high through-plane thermal conductivity (& lambda;(& BOTTOM;)); however, achieving that proved devilishly challenging.Herein, inspired by the structure of the natural shell nacre and basedon the construction of a cis-polybutadiene (BR) vitrimernetwork with reversible B-O bonds, the nacre-mimetic microstructurewith vertically aligned hexagonal boron nitride (BN) was rationallydesigned and fabricated. Combining the hot-pressed orientation withthe stacking-welding method, the vertically aligned BN/BR composite(VAC) was obtained by longitudinal slicing, and the designed microstructurewith intense orientation was verified by scanning electron microscopyand small-angle X-ray scattering. As a result, the VAC reached anunprecedented & lambda;(& BOTTOM;) of 14.1 W & BULL;m(-1)& BULL;K-1 as the BN content was 52 vol %, and therunning chip temperature was greatly reduced compared with that ofcommercial TIM. Besides the superior thermal conductivity, the BN/BRcomposite has excellent electrical insulation and flame resistance.It is believed that the simple fabrication and extendibility of thebiomimetic composites pave a new way for the design and preparationof high-performance TIMs.