Interfacial anchoring via thin –OH functional enables hydration-resistant, enhanced thermal conductivity MgO composites

초록

The increasing power density and miniaturization of electronic devices demand thermal interface materials (TIMs) that integrate high thermal conductivity with long-term environmental stability to ensure reliable performance and durability. Although magnesium oxide (MgO) offers relatively high intrinsic thermal conductivity and isotropic heat transport, its susceptibility to hydration limits practical application in high-humidity operating conditions. Herein, we present a synergistic surface-engineering strategy involving controlled hydroxylation of MgO followed by polypropylene carbonate (PPC) coating to simultaneously enhance hydration resistance and interfacial heat transfer. Surface hydroxylation forms a nanoscale Mg(OH)2 shell enriched with surface hydroxyl groups, enabling strong chemisorption and multidentate anchoring of PPC chains. The resulting PPC layer serves as a robust hydrophobic barrier while improving interfacial compatibility with the epoxy matrix. Epoxy composites containing 60 wt% h-Mg(OH)2–PPC achieved a maximum thermal conductivity of 2.17 W/m·K, corresponding to an 82.4% enhancement compared to untreated MgO composites. This study demonstrates that interfacial anchoring via thin hydroxyl functionalization combined with polymer coating provides an effective route to achieving hydration-resistant, high-performance MgO-based TIMs. The functionalized MgO fillers are expected to demonstrate enhanced performance over that of current commercial filler systems for battery modules and advanced electronic packaging applications. © 2026 Elsevier B.V.

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