Ian Daniell SantosPatrick TjarksJeyavelan MuthuYou-Chen LinZhi-Long YenPradyumna Kumar ChandRadha RamanDinh Tuan NguyenMehdi RouhaniYeau-Ren JengYa-Ping HsiehMario Hofmann2025-01-092025-01-092024-06-27https://scholars.lib.ntu.edu.tw/handle/123456789/724685We demonstrate the strengthening of graphene, an atomically thin carbon allotrope, by out-of-plane folding. Through lateral confinement of graphene at the water-air interface, nanoscale buckling was induced in suspended flakes, leading to an unexpected folding transition beyond a critical surface pressure. The emergence of folding was confirmed by in situ Brewster angle reflectivity and ex situ microscopy, showing a unique “z-laminated” nanostructure. Molecular dynamics simulations indicate that z-lamination yields an enhanced adhesion between neighboring flakes compared to lateral sliding, which was confirmed by a surface pressure hysteresis during the folding process. Mechanical testing reveals superior Young’s modulus and yield strength when compared to conventional graphene assemblies and even compared to composites. We demonstrate the potential of the z-lamination approach for applications in graphene-based structural materials, tribological layers, and functional electrochemical coatings. Finally, the complete recyclability of z-laminated graphene opens up new routes toward sustainable nanostructured materials.2D materialscompositeslaminated graphenemembranesrecyclablejournal article10.1021/acsanm.4c00954