Plasma-assisted self-assembled monolayers for reducing thermal resistance across graphite films/polymer interfaces

Abstract

Graphite-related materials are commonly used as fillers in polymers to prepare thermal interface materials (TIMs) with high thermal conductivity. The thermal contact resistance (TCR) between graphite and polymer is a crucial factor affecting the thermal conductivity of TIMs. However, reducing the TCR is challenging due to the highly stable surface of graphite. Here, we propose a plasma-assisted strategy to form a self-assembled monolayer (SAM) on the surface of graphite films to reduce the TCR of the graphite film/silicone systems. A series of measurements, including the contact angle and Fourier infrared spectrum, confirm the formation of SAM. Using the non-contact photothermal technique, we investigate the effects of plasma bombardment times and powers on the TCR. Under 30 min bombardment, the TCR between modified graphite and silicone is reduced by almost one order of magnitude than the original one. Atomic-scale molecular dynamics simulations further confirm the effectiveness of SAM in reducing the TCR. This plasma-assisted SAM strategy can help graphite-based TIMs to provide better thermal performance to meet the requirements of future high-power devices.