Fig. 1: Manufacture of the graphene-PMMA laminate (GPL) via float-stacking process.

a Schematic of the float-stacking process of the GPL. (i) Floating the graphene–PMMA membrane (GPM) on DI water bath after wet-etching of the bottom Cu foil, (ii) Layer-by-layer stacking of GPMs by rolling process, (iii) Cutting and unfolding of stacked-GPM, and (iv) Hot-rolling mill process of the stacked-GPM. b Photograph of the as-prepared GPL with 100 layers of GPM (GPL − 100). c, d Cross-sectional SEM and TEM images of the GPL − 100. Monolayer graphene is placed between the PMMA matrix without structure defects. Scale bars: 60 μm and 5 nm, respectively.