Three-dimensional self-folding assembly of multi-layer graphene at the interface with a polymeric film

Three-dimensional (3D) architectures of graphene are of great interest for applications in flexible electronics, supercapacitors, and biointerfaces. Here, we demonstrate that multi-layer graphene (MLG), like single-layer graphene (SLG), can self-fold to form 3D architectures at the interface with a polymeric film. Bilayers composed of graphene and polymeric film tightly adhere to each other and possess a sloped internal strain, which leads to spontaneous rolling to predetermined 3D microscale architectures. The curvature radii of self-folding films can be controlled by changing the thicknesses of the polymeric film and the stacking order. In contrast to single-layer graphene, multi-layer graphene shows no strain in most of the outer graphene layers and linear ohmic current characteristics after self-folding. Throughout the self-folding process, the conductance of MLG decreases but remains higher than that of SLG. This versatile way of forming a 3D multi-layer graphene structure is potentially applicable for fabrication of practical carbon devices without the changes in their conductive properties.