Preparation and Vertical Heat Dissipation Performance of PI @ VGNs / Al 2 O 3 Composite Film

ABSTRACT With the rapid development of electronic devices toward high power density and miniaturization, thermal interface materials (TIMs) are needed for the fabrication of integrated circuits with high reliability and performance. Polyimide (PI), due to its low density, corrosion resistance, simple molding and processing, has the largest usage and the fastest development among TIMs. However, unlike ceramic and metal materials that contain regular crystal regions, the existence of a large number of amorphous regions inside PI will cause phonon scattering occurring between different structural interfaces, so high thermal conductive fillers are introduced to improve its thermal conductivity. The point‐plane hybrid fillers composed of vertical graphene nanosheets (VGNs) and Al 2 O 3 particles can improve the tightness of the PI matrix, play the synergistic effect of each component, and the filler is easier to connect with each other to form an effective thermal conductivity path in the PI matrix, so as to improve the vertical thermal conductivity of the PI‐based composite. The vertical thermal conductivity of the PI@VGNs/Al 2 O 3 composite film reaches 0.60 W/(m·K), which is 172.7% and 76.5% higher than that of pure PI film (0.22 W/(m·K)) and PI@VGNs composite film (0.34 W/(m·K)), respectively, indicating their significant potential for applications in heat dissipation technologies.