Abstract
We report that lightweight, anisotropic, mechanically flexible, and high performance thermally insulating materials are fabricated by the assembly of graphene oxide (GO) and polyimide (PI). With an appropriate ratio between GO and PI building blocks, the rGO/PI thermally insulating material exhibits hierarchically aligned microstructures with high porosity. These microstructures endow the rGO/PI nanocomposite with low mass density and super-insulating property (extremely low thermal conductivity of 0.012 W m(-1) K(-1) in the radial direction). Meanwhile, the introduction of PI enhances the mechanical strength and thermal stability of rGO foam. Our rGO/PI nanocomposites as super-insulating foams with a low thermal conductivity are highly attractive for potential thermal insulation applications in aerospace, wearable devices, and energy-efficient buildings.