| AVS 63rd International Symposium & Exhibition | |
| 2D Materials Focus Topic | Wednesday Sessions |
| Session 2D+NS-WeA |
| Session: | Nanostructures including Heterostructures made of 2D Materials |
| Presenter: | Tobin Filleter, University of Toronto, Canada |
| Authors: | T. Filleter, University of Toronto, Canada C. Cao, University of Toronto, Canada J.Y. Howe, Hitachi High Technologies Canada Inc., Canada D. Perovic, University of Toronto, Canada Y. Sun, Univeristy of Toronto, Canada |
| Correspondent: | Click to Email |
Graphene Oxide (GO) is a functionalized form of graphene that we have recently shown to possess high tensile strength [1-2]. These studies on the strength of GO have revealed a size dependent mechanical behavior in which the strength is found to increase with decreasing thickness, a behavior which is controlled by a transition in the fracture mechanism [2]. In real engineering applications in which materials exhibit pre-existing flaws, the fracture toughness of a material is also a critical property in predicting the failure of the material. Here we present studies of GO with preexisting defects that enable the first measurements of the fracture toughness of GO nanosheets. Application of traditional experimental techniques used to measure the fracture toughness (and monitor the fracture behavior) of bulk materials is not feasible for the measurement of ultra-thin films such as GO. In this work, we apply a micro-electro-mechanical system (MEMS) based in situ transmission electron microscope (TEM) method to measure the fracture toughness of GO and directly characterize its fracture behavior through high resolution TEM imaging. GO nanosheets suspended on monolithic MEMS devices in situ TEM were first controllably etched by high-energy electrons to create well defined holes in the GO nanosheets used for fracture toughness measurements. After a defect was created, in situ TEM tensile tests allowed both measurement of the stress at the onset of fracture, as well as direct monitoring of the fracture response via TEM imaging.
[1] C. Cao, M. Daly, C. V. Singh, Y. Sun, and T. Filleter, “High strength measurement of monolayer graphene oxide", Carbon, vol. 81 (2015) p.g. 497-504
[2] C. Cao, M. Daly, B. Chen, J. Howe, C. V. Singh, T. Filleter, and Y. Sun, “Stengthening in graphene oxide nanosheets: bridging the gap between interplanar and intraplanar fracture", Nano Letters, vol. 15 (2016) p.g. 6528-6534