Journal Article

Self-Modifying Nanointerface Driving Ultrahigh Bidirectional Thermal Conductivity Boron Nitride-Based Composite Flexible Films

Zhang, Xinyu, Zhang, Honggang, Chen, Min, Li, Yongwei, Wu, Limin, Huang, Taoqing, Wang, Tian, Bao, Hua

2023

Overview

HighlightsThe flexible composite film presents ultrahigh thermal conductivity and good thermal management performance in electronic devices.An original “self-modified nanointerface” strategy is used to reduce the interfacial thermal resistance between boron nitride and the polymer matrix.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.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 W m−1 K−1 but also, more importantly, achieve a through-plane thermal conductivity as high as 21.3 W m−1 K−1, 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.

• Publisher: Springer Nature B.V
• Subject: Boron / Boron nitride / Composite materials / Dielectric properties / Electronic devices / Fillers / Heat conductivity / Heat transfer / Matching / Nanocrystals / Phonons / Polymers / Thermal conductivity / Thermal management / Thermal resistance