Investigation on the thermal properties of carbon fiber-enhanced thermal interface materials

Abstract

As electronic devices become increasingly compact and densely integrated, the rise in power density presents significant challenges in heat dissipation. The devices’ performance, stability, and reliability are highly depended on the effective thermal management, and the development of high-performance thermal interface materials (TIMs) plays a significantly important role in this aspect. Among various fillers, carbon fiber (CF) offers exceptionally high axial thermal conductivity (>900 W m⁻¹ K⁻¹), although its inherently low radial conductivity and random dispersion limit overall thermal performance. To fully exploit its potentials, both microstructural alignment and interfacial engineering are required to enhance phonon transport across interfaces.

With this, this study systematically explores the structural design and fabrication of CF-based TIMs via three strategic steps: (i) to address the challenge of electrical insulation in CFs, a dense silicon carbide (SiC) layer was deposited via chemical vapor deposition. The resulting CFs@SiC were embedded in a polydimethylsiloxane (PDMS) matrix through melt blending to form isotropic TIMs, achieving a thermal conductivity of 3.09 W m⁻¹ K⁻¹; (ii) to further enhance directional heat transport, a direct ink writing (DIW) 3D printing method was employed to align CFs vertically within the matrix, significantly boosting through-plane thermal conductivity to 35.22 W m⁻¹ K⁻¹; (iii) to address the elevated interfacial thermal resistance persisted due to the rough CF terminations at the interface, a sandwich TIM structure was then developed, incorporating liquid metal (LM)-modified interfacial layers to reduce contact resistance. Using a rolling–stacking method, these composites achieved a maximum thermal conductivity of 51.90 W m⁻¹ K⁻¹ and a total thermal resistance of 0.32 K cm² W⁻¹.

Overall, this dissertation presents a comprehensive framework for advancing CF-based TIMs through synergistic alignment control, surface modification, and scalable processing. The proposed materials offer strong potential for next-generation high-power electronics and RF systems. Furthermore, this work contributes valuable insights into phonon transport mechanisms and interface behavior, establishing a foundation for the rational design of high-efficiency thermal management materials.

Date of Award	15 Jan 2026
Original language	English
Awarding Institution	University of Nottingham
Supervisor	Haonan Li (Supervisor), Nan Jiang (Supervisor) & Chung Ket Thein (Supervisor)