Enhancing Thermal Conductivity through Interface Modification: Experimental and Theoretical Validation for a Polymer–Metal Film

Polymer–metal composite materials have been extensively employed for thermal management in the electronic field. However, their application is hindered by limited thermal conductivity and inadequate electrical insulation. In this study, we present a novel strategy to prepare advanced polymer–metal films by incorporating cellulose nanofibers (CNFs) with orientated polydopamine (PDA) modified aluminum (Al) flakes, employing a straightforward process involving vacuum-assisted filtration and hot-pressing. The resulting Al@PDA/CNF films exhibited a superior in-plane thermal conductivity of 22.9 W/(m·K) and electrical resistivity of 1.6 × 1016 Ω·cm, outperforming the Al/CNF films. Molecular dynamics simulation results showed that the interfacial interaction between Al and CNF was greatly improved by the hydrogen-bonding interaction with coated PDA, which acts as a "bridge" to promote phonon vibration matching, resulting in excellent heat transfer and electrical insulation properties. Our study provides a promising approach for the preparation of high-performance polymer–metal thermal interface materials (TIMs) with insulation, demonstrating great potential in thermal management applications.