International audienceIt is demonstrated that a graphene-based film (GBF) functionalized with silane molecules strongly enhances thermal performance. The resistance temperature detector results show that the inclusion of silane molecules doubles the heat spreading ability. Furthermore, molecular dynamics simulations show that the thermal conductivity (κ) of the GBF increased by 15%–56% with respect to the number density of molecules compared to that with the nonfunctionalized graphene substrate. This increase in κ is attributed to the enhanced in-plane heat conduction of the GBF, resulting from the simultaneous increase of the thermal resistance between the GBF and the functionalized substrate limiting cross-plane phonon scattering. Enhancement of the thermal performance by inserting silane-functionalized molecules is important for the development of next-generation electronic devices and proposed application of GBFs for thermal management

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With the development of renewable energy resources, polymer-based dielectric materials, as key components in energy storage devices with optimized dielectric property, high-temperature stability, and good processibility, are highly demanded. In this study, p-phenylenediamine (PPD)-modified and l-ascorbic acid (LAA)-reduced graphene oxide (NH2-CRG) nanosheets with significant chemical functionalization and significantly improved dispersity were prepared. Also, polyimide was chosen to be the polymer matrix due to its high-temperature resistance, chemical inertness, and excellent mechanical property. By incorporating NH2-CRG into the PI polymer matrix via in situ polymerization, 0.8 wt % NH2-CRG/PI composite material with a dielectric constant as high as 839 and a breakdown strength of 80 kV·mm–1 was obtained. Meanwhile, the 5 wt % weight loss temperature of 0.8 wt % NH2-CRG/PI witnessed a 17.6 °C increase compared to pure PI. This work provided a promising strategy to prepare graphene-based materials for high-dielectric applications and a realizable process of fabricating polymer-based dielectric composite materials.

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