With the miniaturization and high integration development in microelectronic devices, the problem of heat dissipation has attracted widespread attention. Highly thermal conductive and electrical insulation polymer composites show great advantages to solve the problems of heat dissipation. Nevertheless, the fabrication of polymer composites with both excellent thermal conductivity and electrical performance is still a great challenge. Herein, to coordinate the thermal and electrical properties of the composite film, the sandwich-structured poly(vinyl alcohol) (PVA)/boron phosphide (BP)-boron nitride nanosheet (BNNS) composite films were prepared, with the PVA/BP composite film as the top and bottom layers and the BNNS layer as the middle layer. When the filler loading was 31.92 wt %, the sandwich-structured composite films showed excellent in-plane thermal conductivity (9.45 W·m-1·K-1), low dielectric constant (1.25 at 102 Hz), and excellent breakdown strength. In the composite film, the interconnected BP particles and BNNS layer formed several heat dissipation pathways to increase the thermal conductivity, while the insulated BNNS layer hampered the electron transformation to enhance the electrical resistivity of films. Therefore, the PVA/BP-BNNS composite films showed a potential application in heat dissipation of high power electronic devices.
Keywords: boron phosphide; composite film; dielectric performance; sandwich structure; thermal conductivity.