Synergistic Improvement in Thermal Conductivity of Polyimide Nanocomposite Films Using Boron Nitride Coated Copper Nanoparticles and Nanowires.

Yongcun Zhou,Feng Liu,Huan Niu,Shihu Yu

doi:10.3390/polym10121412

Abstract

Electronic devices are increasingly dense, underscoring the need for effective thermal management. A polyimide (PI) matrix nanocomposite film combining boron nitride (BN)-coated copper nanoparticles (CuNPs@BN) and nanowires (CuNWs@BN) was fabricated by a flexible and fast technique for enhanced thermal conductivity and the dielectric properties of nanocomposite films. The thermal conductivity of (CuNPs-CuNWs)@BN/PI composite comprising 10 wt % filler loading rose to 4.32 W/mK, indicating a nearly 24.1-fold increase relative to the value obtained for pure PI matrix. The relative permittivity and dielectric loss approximated 4.92 and 0.026 at 1 MHz, respectively. The results indicated that the surface modification of CuNPs and CuNWs by introducing a ceramic insulating layer BN effectively promoted the formation of thermal conductive networks of nanofillers in the PI matrix. This study enabled the identification of appropriate modifier fillers for polymer matrix nanocomposites to improve electronic applications.

Highlights

Surface modifications of fillers in polymer matrix composite films attract increasing attention because of as-created core-shell structures possessing extraordinary features, including their use as biocatalysts, phase change materials, and other potential applications [1–3]
SEM micrographs of CuNPs, CuNPs@boron nitride (BN), CuNWs, CuNWs@BN, and (CuNPs-CuNWs)@BN/PI
CuNPs, CuNPs@BN, CuNWs, CuNWs@BN, and are depicted in Figure 2a–c,e–g, respectively; TEM micrographs of core-shell CuNPs@BN and (CuNPs-CuNWs)@BN/PI are depicted in Figure 2a,b,e,f,c,g, respectively; TEM micrographs of

Summary

Introduction

Surface modifications of fillers in polymer matrix composite films attract increasing attention because of as-created core-shell structures possessing extraordinary features, including their use as biocatalysts, phase change materials, and other potential applications [1–3]. (CuNWs) are excellent candidates for orientation fillers in polymer matrix composite films with high thermal conductivity [6–13]. The properties of copper, including elevated thermal conductivity and low relative permittivity, still need improvement for more applications as a filler of polymer matrix composites. A novel approach was developed through the surface modification of CuNPs and CuNWs using synthetic BN to generate flexible polyimide (PI) nanocomposites displaying elevated thermal conductivity but minimal relative permittivity. CuNWs (denoted as CuNPs@BN and CuNWs@BN, respectively) formed a barrier that prevented the generation of conductive paths, effectively reducing the dielectric constant of composites This “point-line” structure is considered to play a bridging role for copper nanoparticles with copper nanowires in enhancing the filler interaction to reduce interfacial thermal resistance. The thermal management of PI nanocomposites according to the multilayer-structure comprising BN-coated CuNPs and CuNWs is scarcely studied

Materials

Characterization

Results and Discussion