Functionalization\nof Graphene by Interfacial Engineering\nin Thermally Conductive Nanofibrillated Cellulose Films

Flexible nanocomposites incorporating\nnanofibrillated\ncellulose\n(NFC) hold significant promise for thermal management applications.\nHowever, their heat dissipation performance is primarily constrained\nby the interfacial thermal resistance (<i>R</i><sub>bd</sub>). In this work, 1-pyrenemethylamine hydrochloride (PyNH<sub>2</sub>) noncovalent functionalized graphene subsequently self-assembled\nwith NFC through a vacuum-assisted filtration technique. PyNH<sub>2</sub> could not only stabilize graphene with π–π\nconjugation but also interact with NFC via hydrogen bonding. The prepared\nlayered-structure nanocomposites achieve a thermal conductivity of\n11.32 W·m<sup>–1</sup>·K<sup>–1</sup> with\na low filler content of just 5 wt %. Utilizing the effective medium\napproximation (EMA) method and two-dimensional X-ray scattering techniques,\nwe know that this satisfactory thermal conductivity is mainly attributed\nto pyrene functionalization of graphene by interfacial engineering-induced\nlow <i>R</i><sub>bd</sub> and high orientation degree of\ngraphene. Undoubtedly, this study provides experimental and theoretical\nguide for fabrication of thermal conductive nanocomposites in the\nnear future.