Exploring the Aging Characteristics of Poly(Ionic Liquid)S-Based Thermal Interface Materials

Thermal interface materials (TIMs) are essential for managing heat in electronics. Silicone systems face challenges such as leakage of silane molecules, limited mechanical flexibility, poor filler compatibility and weak interfacial adhesion. In contrast, poly(ionic liquid)s (PILs) have emerged as promising alternatives due to their exceptional mechanical flexibility, thermal stability, robust interfacial adhesion across various substrates, filler compatibility, self-healing properties, and reprocessability. Yet, a critical gap exists in the thermo-physical and reliability characterization of PILs and their composites. This study introduces a novel TIM composed of PILs and Ga-based liquid metal (LM). The strong interaction between PILs and LM imparts the obtained composites a certain degree of flexibility and superior interface adhesion, making it suitable for use as TIMs. Specifically, the obtained TIM (80% mass fraction of LM) possesses a thermal conductivity of 1.2 W/(m.K) and exhibit an interfacial adhesion strength of 1.1 MPa with silicon, excellent thermal stability (>350°C). Furthermore, the aging characteristics of PIL and its composites with LM were also evaluated in terms of coverage change. This work established a critical foundation for the feasibility study of PIL as a TIM matrix.