Influence of oxygen functional groups on the crack growth behavior of graphene with edge and middle crack: A molecular dynamics study

In the last decade, graphene has found a wide role and application in nanocomposites and nanodevices for its extraordinary properties. However, due to its low fracture toughness and brittleness, graphene is brittle, and crack growth occurs rapidly. As a result, crack growth behavior and control of its progression are important. In this study, molecular dynamics modeling was used to investigate the crack growth behavior and mechanical properties in functionalized graphene (with middle and edge crack) with different oxide groups (hydroxyl, epoxide, and carboxyl) at different percentages of graphene oxide (0–3 wt. %). The results show that functionalized graphene with oxide groups changes the properties of graphene, effectively reducing the crack growth in crack length (4.9 Å), crack opening displacement (1.4 Å), tensile strength for edge crack (74 to 54 Gpa), and middle crack (128 to 63 Gpa). Also, carboxyl and epoxide groups have a greater reduction in crack growth rate, opening displacement growth rate, and stress concentration. In addition, increase in the number of atoms in oxide groups around the initial crack (with radius 13 Å) reduces crack growth rate, opening displacement growth rate, and stress concentration. This study provides a broader insight into crack growth behavior in functionalized graphene with oxide groups.