Temperature dependent thermal conductivity of free-standing reduced graphene oxide/poly (vinylidene fluoride-co-hexafluoropropylene) composite thin film

This work reports on the thermal conductivity of a reduced graphene oxide (rGO)/poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer composite thin film at a very low fraction of 0.25 wt% rGO. The composite thin film was prepared through a simple solution casting of GO/PVDF-HFP dispersion, followed by low temperature chemical reduction. It was observed that free-standing rGO/PVDF-HFP composite thin film exhibited room temperature thermal conductivity of ∼2.35 W/mK only at 0.25 wt% of rGO concentration, which is 100 times higher than that of pristine PVDF-HFP film (∼0.2 W/mK). Further, measurements showed that the composite film possessed highly temperature dependent thermal conductivity. The thermal conductivity values increased from 2.35 W/ mK to ∼5.53 W/ mK in the temperature range from 25 to 125 °C. This flexible and lightweight rGO/PVDF-HFP composite thin film with efficient thermal conductivity would be helpful for the design of lightweight thermally conductive interface materials for aircraft, spacecraft and automobiles applications. (paper)