Improving Interfacial Thermal Transport in Silicon-Reinforced Epoxy Resin Composites with Self-Assembled Monolayers

Abstract

Epoxy resin (EP) based composite materials, due to their advantages such as light weight, ease of processing, and mechanical properties, have been widely applied across thermal packaging field. However, their inherent low thermal conductivity necessitates the incorporation of high thermal conductivity fillers to enhance overall thermal performance. A persistent issue limiting this thermal conductivity is the interface thermal resistance of fillers within the substrate. Consequently, the interfacial thermal conductance (ITC) is a critical factor in determining the thermal conductivity of polymer composites. Here, we utilized time-domain thermoreflectance (TDTR) experiment and molecular dynamics (MD) simulation to adjust the ITC of EP/silicon (Si) interfaces modified with self-assembled monolayers (SAM) by forming either bilateral covalent bonds or single covalent bond. The interface modified with SAM-NH₂, providing high adhesion strength and excellent vibrational matching, enhanced the ITC to 140%, thereby promoting heat transfer performance across interfaces. Conversely, the ITC decreased due to the formation of single covalent bonds with SAM-CH₃. Subsequently, through the Differential Effective Medium (DEM) model, it was determined that the thermal conductivity of composite materials (kc) modified with SAM-NH₂ increased by 11%. This research provides novel insights into adjusting ITC using SAM.

Keywords: interfacial thermal conductance, self-assembled monolayers, organic thermal conductive composite, time-domain thermoreflectance, molecular dynamics