Graphene\nOrigami with Highly Tunable Coefficient of\nThermal Expansion

Abstract

The\ncoefficient of thermal expansion, which measures the change\nin length, area, or volume of a material upon heating, is a fundamental\nparameter with great relevance for many applications. Although there\nare various routes to design materials with targeted coefficient of\nthermal expansion at the macroscale, no approaches exist to achieve\na wide range of values in graphene-based structures. Here, we use\nmolecular dynamics simulations to show that graphene origami structures\nobtained through pattern-based surface functionalization provide tunable\ncoefficients of thermal expansion from large negative to large positive.\nWe show that the mechanisms giving rise to this property are exclusive\nto graphene origami structures, emerging from a combination of surface\nfunctionalization, large out-of-plane thermal fluctuations, and the\nthree-dimensional geometry of origami structures.