Functionalized graphene origami metamaterials with tunable thermal conductivity

Graphene with tunable thermo-mechanical property is of great importance for next-generation thermal management devices. Distinct from previously reported porous graphene materials that tune the thermal conductivity at the cost of degrading their mechanical properties, non-porous hydrogenated graphene origami metamaterial exhibits a unique combination of tunable thermal conductivity, high strength, and enhanced stretchability. Through molecular dynamics simulation, a vast range of thermal conductivity can be found by tuning the geometrical parameters of the Miura-ori graphene origami, altering the adatom types and density, designing new origami patterns, and applying mechanical strains. By analyzing and comparing the numerical results from atomistic and continuum-based simulations, the effect of length scale on the thermal property of graphene origami metamaterials is explored. The temperature distribution, phonon density of states, phonon group velocity, and the atomic heat flux of the graphene origami are examined to illustrate the heat conduction mechanism. Finally, 3D graphene origami metamaterials are constructed by assembling the graphene origami strips, followed by evaluating their thermo-mechanical performance. Negative coefficients of thermal expansion are also observed in the functionalized graphene origami nanotubes. The introduced strategy for controlling the thermo-mechanical properties of graphene metamaterials can open up new avenues for developing thermoelectric devices, heat management systems, and flexible nanoelectronics. • Surface functionalization-induced reconfigurable graphene origami. • Combination of tunable thermal conductivity, high strength, and stretchability. • A broad tunability range of thermal conductivity by mechanical strains. • 3D graphene origami nanoarchitected metamaterials by assembling graphene origami. • Negative coefficients of thermal expansion in 3D graphene origami.