Construction of Thermal Bridge in Alumina/Polydimethylsiloxane Composites by Selective Location of Erythritol

Alumina/polymer composites are conventional thermal interface materials widely used for heat dissipation. However, the interfacial thermal resistance (ITR) dominates the thermal conductivity (TC) of these composites, presenting a critical challenge. This study introduces erythritol as an innovative thermal bridge to effectively reduce the ITR by selectively locating it at the interfaces among alumina (Al₂O₃) particles. Through a straightforward preparation method, erythritol was positioned among Al₂O₃ particles, followed by the impregnation of poly(dimethylsiloxane) (PDMS) into the filler gaps. The resulting Al₂O₃/erythritol/PDMS composite demonstrated a thermal conductivity of 3.12 W·m^-1·K^-1 at an erythritol content of 4.16 wt % and a filler content of 53.7 vol %. Minor usage of erythritol brings a 34.4% enhancement compared with conventional Al₂O₃/PDMS composites. Additionally, the composite shows potential as a thermal switch due to erythritol's phase change properties. This approach, which emphasizes fluid-state processing and interface bridging, presents a promising new strategy for improving the thermal conductivity of ceramic-filled polymer composites.