Liquid evaporation-driven folding of graphene sheets

We propose a theory of folding graphene sheets from rapid evaporation of its liquid suspension. Using an energy criterion that contains the competition among bending energy of graphene sheets, surface energy of graphene sheets and liquid and their interfacial energy, and binding energy of folded graphene sheets, we are able to quantitatively correlate folded three-dimensional (3D) graphene structures with both geometric size and surface wettability of original graphene sheets. Theoretical predictions of folded 3D graphene patterns and sizes agree well with the parallel molecular dynamics simulations. Our theory is of immediate interest to the study of crumpling/folding original two-dimensional structures to 3D shapes through evaporation of a liquid suspension. (C) 2016 AIP Publishing LLC.