Layer‐by‐Layer Assembled g‐C3N4 Nanosheets/Cellulose Nanofibers Oriented Membrane‐Filler Leading to Enhanced Thermal Conductivity

Abstract Thermally conducting but electrically insulating materials attract much attention because of miniaturization and high‐degree integration of modern electronic. The traditional approaches to prepare the thermally conductive polymer nanocomposites are usually influenced by the low thermal conductivity, deterioration of electrically insulating, and high filler amount. One of the main reasons is that the filler is impossible to construct an effective heat conductive pathway. In this work, the “lasagna” g‐C 3 N 4 /nanofiber cellulose (NFC) thermal conducting membrane‐filler (MF) is first proposed to address these issues. This membrane‐filler is curled to form a cylinder, and then an anisotropic thermally conductive nanocomposite is fabricated by impregnation of PDMS into the cylinder. The g‐C 3 N 4 can arrange along the direction of heat transfer to create an effective phonon transmission pathway. The thermal conductivity not only achieves 1.94 W m −1 K −1 at a low g‐C 3 N 4 /NFC MF loading of 9.16 vol% but also exhibits outstanding electrical insulant. Meanwhile, the thermal conductivity of g‐C 3 N 4 is systematically investigated using the nonequilibrium molecule dynamics simulations. This strategy represents a facile, efficient approach to the design of high‐performance nanocomposites with potential application for thermal management materials.