Thermal percolation and electrical insulation in composite materials with partially metallic coated fillers

TL;DR

This paper introduces a new composite material design with partially metallic coated nanowires that achieves high thermal conductivity through percolation while maintaining electrical insulation, guiding efficient thermal interface material development.

Contribution

It proposes the concept of thermal-percolation electrical-insulation and provides a design framework for hybrid thermal interface materials with controlled electrical and thermal properties.

Findings

High thermal conductivity achieved via thermal percolation.

Electrical insulation maintained by controlling coating and volume fraction.

Electrical conductivity can be tuned by coating configuration.

Abstract

We propose a type of thermal interface materials incorporating insulating nanowires with partially metallic coating in insulating polymer matrix.Large thermal conductivity can be obtained due to thermal percolation while the electrical insulation is maintained by controlling $C_{\rm M}\varphi < \varphi_{\rm c}^{\rm e}$ and $\varphi > \varphi_{\rm c}^{\rm th}$, where $\varphi$ is the volume fraction of filler, $C_{\rm M}$ is the metallic coating fraction, $\varphi_{\rm c}^{\rm e}$ and $\varphi_{\rm c}^{\rm th}$ are the electrical and thermal percolation thresholds, respectively. The electrical conductivity of such composite materials can further be regulated by coating configuration. In this regard, we propose the concept of "thermal-percolation electrical-insulation", providing a guide to design efficient hybrid thermal interface materials.