TY - JOUR AU - Huang, Taoqing AU - Zhang, Xinyu AU - Wang, Tian AU - Zhang, Honggang AU - Li, Yongwei AU - Bao, Hua AU - Chen, Min AU - Wu, Limin PY - 2022/12/04 Y2 - 2024/03/29 TI - Self-Modifying Nanointerface Driving Ultrahigh Bidirectional Thermal Conductivity Boron Nitride-Based Composite Flexible Films JF - Nano-Micro Letters JA - Nano-Micro Lett VL - 15 IS - SE - Articles DO - 10.1007/s40820-022-00972-9 UR - https://nmlett.org/index.php/nml/article/view/1226 SP - 2 AB - <p>While boron nitride (BN) is widely recognized as the most promising thermally conductive filler for rapidly developing high-power electronic devices due to its excellent thermal conductivity and dielectric properties, a great challenge is the poor vertical thermal conductivity when embedded in composites owing to the poor interfacial interaction causing severe phonon scattering. Here, we report a novel surface modification strategy called the “self-modified nanointerface” using BN nanocrystals (BNNCs) to efficiently link the interface between BN and the polymer matrix. Combining with ice-press assembly method, an only 25 wt% BN-embedded composite film can not only possess an in-plane thermal conductivity of 20.3&nbsp;W&nbsp;m<sup>−1</sup>&nbsp;K<sup>−1</sup> but also, more importantly, achieve a through-plane thermal conductivity as high as 21.3&nbsp;W&nbsp;m<sup>−1</sup>&nbsp;K<sup>−1</sup>, which is more than twice the reported maximum due to the ideal phonon spectrum matching between BNNCs and BN fillers, the strong interaction between the self-modified fillers and polymer matrix, as well as ladder-structured BN skeleton. The excellent thermal conductivity has been verified by theoretical calculations and the heat dissipation of a CPU. This study provides an innovative design principle to tailor composite interfaces and opens up a new path to develop high-performance composites.</p><p>Highlights:</p><p>1 The flexible composite film presents ultrahigh thermal conductivity and good thermal management performance in electronic devices.<br>2 An original “self-modified nanointerface” strategy is used to reduce the interfacial thermal resistance between boron nitride and the polymer matrix.<br>3 The ideal phonon spectrum matching between boron nitride nanocrystals and fillers as well as the strong interaction between self-modified fillers and the polymer matrix are the two major contributors to decrease the interfacial thermal resistance.</p> ER -