Highly Thermally Conductive Polydimethylsiloxane Composites with Controllable 3D GO@f-CNTs Networks via Self-sacrificing Template Method

Constructing controllable thermal conduction networks is the key to efficiently improve thermal conductivities of polymer composites. In this work, graphite oxide (GO) and functionalized carbon nanotubes (f-CNTs) are combined to prepare “Line-Plane”-like hetero-structured thermally conductive GO@f-CNTs fillers, which are then performed to construct controllable 3D GO@f-CNTs thermal conduction networks via self-sacrificing template method based on oxalic acid. Subsequently, thermally conductive GO@f-CNTs/polydimethylsiloxane (PDMS) composites are fabricated via casting method. When the size of oxalic acid is 0.24 mm and the volume fraction of GO@f-CNTs is 60 vol%, GO@f-CNTs/PDMS composites present the optimal thermal conductivity coefficient (λ, 4.00 W·m⁻¹·K⁻¹), about 20 times that of the λ of neat PDMS (0.20 W·m⁻¹·K⁻¹), also much higher than the λ (2.44 W·m⁻¹·K⁻¹) of GO/f-CNTs/PDMS composites with the same amount of randomly dispersed fillers. Meanwhile, the obtained GO@f-CNTs/PDMS composites have excellent thermal stability, whose λ deviation is only about 3% after 500 thermal cycles (20–200 °C).