Flexible and high-temperature dielectric ANF-NFC/mica@PDA composite film with high breakdown strength

Traditional mica-based composites are limited to the application in high-voltage electric insulation by their underdeveloped breakdown strength and mechanical robustness. Herein, a novel double-network mica-based composite film was fabricated by introducing aramid nanofiber (ANF) and nanofibrillated cellulose (NFC), which cooperatively enhanced interfacial adhesion and reinforcing effect. The ANF-NFC/mica@PDA composite film exhibited high mechanical strength (~ 28.76 MPa), excellent dielectric breakdown strength (~ 33.45 kV/mm) and positive mechanical flexibility. Moreover, the composite represented stable dielectric property at high temperature, which meant the ANF-NFC/mica@PDA composite film could be applied in more complex environments. This work provides a new route toward manufacturing superior performance mica-based composites for the electrical insulation field.