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

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.

Thermal Transport in 3D Nanostructures

“…When an effective percolation network is formed at higher filler loading, the high thermal conductivity of the NWs will significantly enhance the heat transfer, as is seen from the PA composite with long Cu NWs in Figure a. Since long NWs are beneficial for the conductive network formation, the composites exhibit a much high κ reinforced by long NWs in comparison with the counterpart reinforced by short NWs (under a same filler content) 245b. Experimental results reveal that a proper coating can not only resume a high electrical resistivity, but also enhance the phonon propagation across the NW/matrix interface and promote a further enhance to the heat transfer in the composites .…”

“…Besides the carbon‐based and ceramic‐based fillers, metallic nanofillers are also appealing candidates to enhance the heat transfer in polymer composites. They are often in forms of NP and NW with a high aspect ratio (AR, length over diameter). As aforementioned, NWs are preferable for TIMs as they can form effective percolation network at a low filler content.…”

“…Due to the high thermal conductivity of metallic NW filler, the heat transfer in the polymer composites can be remarkably enhanced at a very low filler loading. For instance, with a low volume fraction of 0.9% of Cu NWs (AR = 100–1000), polyacrylate (PA) composite is reported to achieve a high κ of 2.46 W m −1 K −1 245b. Together with the high thermal conductivity, metallic NWs also possess a high electrical conductivity, which usually ruins the electrical insulating properties of the polymer composites.…”

“…Together with the high thermal conductivity, metallic NWs also possess a high electrical conductivity, which usually ruins the electrical insulating properties of the polymer composites. For example, the PA composites with 0.9 vol% of Cu NWs is measured with an electrical conductivity of 0.04 S cm −1 , which are no longer electrical insulting 245b. To overcome this issue, different surface modifications have been proposed for metallic NWs, e.g., grow a nanocoating of SiO 2 or polydopamine (PDA) on the NW surface.…”

Recent Advances in Thermal Interface Materials

“…However, any researchers in this area should benchmark thermal performance of their new concepts with the current commercially available TIMs. [152][153][154][155][156][157][158][159][160][161][162][163][164][165][166] Research should also focus on minimizing the overall thermal resistance instead of just focusing on increasing thermal conductivity. This is because although λ TIM increases with increasing volume fraction, bulk thermal resistance reaches a minimum due to competing effects between the BLT and λ TIM .…”