Paving thermally conductive highway by 3D interconnected framework of carbon nanotube and graphene oxide in poly(vinylidene fluoride)

Polymer-based materials with high thermal conductivity are highly desirable for thermal management applications. In this work, a new hierarchical three-dimensional (3D) framework is built by electrostatic self-assembly between positively charged carbon nanotube (CNT) and negatively charged graphene oxide (GO) in poly(vinylidene fluoride) (PVDF). The obtained composites possess an enhanced thermal conductivity and outstanding mechanical properties simultaneously. Thermal conductivity enhancement of 628% and tensile strength enhancement of 120% are achieved at 10 wt% GO-A-CNT hybrid filler loading compared with that of pure PVDF. Moreover, the GO-A-CNT/PVDF composites exhibit mainly polar γ-form crystallites and sharply decreased crystallinity compared with pure PVDF and CNT/PVDF composites. The theoretical simulation of the effective medium theory is well fitted with experimental observation, which elucidates the significance of 3D framework for more efficient phonon transmit. These GO-A-CNT/PVDF composites may have great potential application as heat exchanger materials.