title: Engineering the Mechanical Properties of Monolayer Graphene Oxide at the Atomic Level.
abstract: The mechanical properties of graphene oxide (GO) are of great importance for applications in materials engineering. Previous mechanochemical studies of GO typically focused on the influence of the degree of oxidation on the mechanical behavior. In this study, using density functional-based tight binding simulations, validated using density functional theory simulations, we reveal that the deformation and failure of GO are strongly dependent on the relative concentrations of epoxide (-O-) and hydroxyl (-OH) functional groups. Hydroxyl groups cause GO to behave as a brittle material; by contrast, epoxide groups enhance material ductility through a mechanically driven epoxide-to-ether functional group transformation. Moreover, with increasing epoxide group concentration, the strain to failure and toughness of GO significantly increases without sacrificing material strength and stiffness. These findings demonstrate that GO should be treated as a versatile, tunable material that may be engineered by controlling chemical composition, rather than as a single, archetypical material.
authors.affiliation: Theoretical and Applied Mechanics Program, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Rafael A
authors.initials: RA
authors.lastname: Soler-Crespo
authors.affiliation: Theoretical and Applied Mechanics Program, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.|Department of Mechanical Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
authors.affiliation: Department of Chemistry and the Institute for Computational Engineering and Sciences, The University of Texas at Austin , Austin, Texas 78712-0165, United States.
authors.forename: Penghao
authors.initials: P
authors.lastname: Xiao
authors.affiliation: Theoretical and Applied Mechanics Program, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.|Department of Mechanical Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Xiaoding
authors.initials: X
authors.lastname: Wei
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.|Department of Chemistry, University of Victoria , Victoria, British Columbia V8W 3 V6, Canada.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Paci
authors.affiliation: Department of Chemistry and the Institute for Computational Engineering and Sciences, The University of Texas at Austin , Austin, Texas 78712-0165, United States.
authors.forename: Graeme
authors.initials: G
authors.lastname: Henkelman
authors.affiliation: Theoretical and Applied Mechanics Program, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.|Department of Mechanical Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Horacio D
authors.initials: HD
authors.lastname: Espinosa