title: Interfacial Shear Strength of Multilayer Graphene Oxide Films.
abstract: Graphene oxide (GO) is considered as one of the most promising layered materials with tunable physical properties and applicability in many important engineering applications. In this work, the interfacial behavior of multilayer GO films was directly investigated via GO-to-GO friction force microscopy, and the interfacial shear strength (ISS) was measured to be 5.3 ± 3.2 MPa. Based on high resolution atomic force microscopy images and the available chemical data, targeted molecular dynamics simulations were performed to evaluate the influence of functional structure, topological defects, and interlayer registry on the shear response of the GO films. Theoretical values for shear strength ranging from 17 to 132 MPa were predicted for the different structures studied, providing upper bounds for the ISS. Computational results also revealed the atomic origins of the stochastic nature of friction measurements. Specifically, the wide scatter in experimental measurements was attributed to variations in functional structure and topological defects within the sliding volume. The findings of this study provide important insight for understanding the significant differences in strength between monolayer and bulk graphene oxide materials and can be useful for engineering topological structures with tunable mechanical properties.
authors.affiliation: Department of Materials Science and Engineering, University of Toronto , 184 College Street, Toronto, ON, Canada M5S 3E4.
authors.forename: Matthew
authors.initials: M
authors.lastname: Daly
authors.affiliation: Department of Mechanical and Industrial Engineering, University of Toronto , 5 King's College Road, Toronto, ON, Canada M5S 3G8.
authors.forename: Changhong
authors.initials: C
authors.lastname: Cao
authors.affiliation: Department of Mechanical and Industrial Engineering, University of Toronto , 5 King's College Road, Toronto, ON, Canada M5S 3G8.
authors.forename: Hao
authors.initials: H
authors.lastname: Sun
authors.affiliation: Department of Mechanical and Industrial Engineering, University of Toronto , 5 King's College Road, Toronto, ON, Canada M5S 3G8.
authors.forename: Yu
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Mechanical and Industrial Engineering, University of Toronto , 5 King's College Road, Toronto, ON, Canada M5S 3G8.
authors.forename: Tobin
authors.initials: T
authors.lastname: Filleter
authors.affiliation: Department of Materials Science and Engineering, University of Toronto , 184 College Street, Toronto, ON, Canada M5S 3E4.
authors.forename: Chandra Veer
authors.initials: CV
authors.lastname: Singh
keywords: friction force microscopy; graphene oxide; interfacial shear strength; mechanical properties; molecular dynamics; shear response