Innocuous, Highly Conductive, and Affordable Thermal Interface Material with Copper-Based Multi-Dimensional Filler Design.

Woochang Kim,Wonseok Lee,Jinsung Park,Duckjong Kim,Chihyun Kim

doi:10.3390/biom11020132

Abstract

Thermal interface materials (TIMs), typically composed of a polymer matrix with good wetting properties and thermally conductive fillers, are applied to the interfaces of mating components to reduce the interfacial thermal resistance. As a filler material, silver has been extensively studied because of its high intrinsic thermal conductivity. However, the high cost of silver and its toxicity has hindered the wide application of silver-based TIMs. Copper is an earth-abundant element and essential micronutrient for humans. In this paper, we present a copper-based multi-dimensional filler composed of three-dimensional microscale copper flakes, one-dimensional multi-walled carbon nanotubes (MWCNTs), and zero-dimensional copper nanoparticles (Cu NPs) to create a safe and low-cost TIM with a high thermal conductivity. Cu NPs synthesized by microwave irradiation of a precursor solution were bound to MWCNTs and mixed with copper flakes and polyimide matrix to obtain a TIM paste, which was stable even in a high-temperature environment. The cross-plane thermal conductivity of the copper-based TIM was 36 W/m/K. Owing to its high thermal conductivity and low cost, the copper-based TIM could be an industrially useful heat-dissipating material in the future.

Highlights

Thermal interface materials (TIMs), typically composed of a polymer matrix with good wetting properties and thermally conductive fillers, are applied to the interfaces of mating components to reduce the interfacial thermal resistance
We introduced an innoxious copper-based multi-dimensional filler composed of 3D microscale copper flakes, 1D multi-walled carbon nanotubes (MWCNTs), and 0D Cu NPs by substituting copper for silver in a multi-dimensional filler design, as demonstrated previously [1,2]
The Cu NPs functionalized with the phenyl groups were mixed with MWCNTs to form MWCNTs assembled with Cu NPs through π–π interactions

Summary

Introduction

Thermal interface materials (TIMs), typically composed of a polymer matrix with good wetting properties and thermally conductive fillers, are applied to the interfaces of mating components to reduce the interfacial thermal resistance. Recent studies have shown the excellent thermal conductivity, printability, and thermal stability of TIMs by introducing a multi-dimensional filler design composed of three-dimensional (3D) microscale Ag flakes, one-dimensional (1D) multi-walled carbon nanotubes (MWCNTs), and zero-dimensional (0D) Ag nanoparticles (Ag NPs) [1,2]. The toxicity of MWCNTs, one of the secondary filler materials, remains a controversial, but recently positive research results related to the safety have been reported. Cimbaluk et al showed that the MWCNTs did not generate an apparent genotoxicity by means of single/double deoxyribonucleic acid strand breaks or clastogenic/aneugenic effects over any of the species, independent of the exposure period, using the alkaline version of the Biomolecules 2021, 11, 132.

Methods

Results

Conclusion