Functionalization of Graphene by Interfacial Engineering in Thermally Conductive Nanofibrillated Cellulose Films

Flexible nanocomposites incorporating nanofibrillated cellulose (NFC) hold significant promise for thermal management applications. However, their heat dissipation performance is primarily constrained by the interfacial thermal resistance (R_bd). In this work, 1-pyrenemethylamine hydrochloride (PyNH₂) noncovalent functionalized graphene subsequently self-assembled with NFC through a vacuum-assisted filtration technique. PyNH₂ could not only stabilize graphene with π-π conjugation but also interact with NFC via hydrogen bonding. The prepared layered-structure nanocomposites achieve a thermal conductivity of 11.32 W·m^-1·K^-1 with a low filler content of just 5 wt %. Utilizing the effective medium approximation (EMA) method and two-dimensional X-ray scattering techniques, we know that this satisfactory thermal conductivity is mainly attributed to pyrene functionalization of graphene by interfacial engineering-induced low R_bd and high orientation degree of graphene. Undoubtedly, this study provides experimental and theoretical guide for fabrication of thermal conductive nanocomposites in the near future.