Mechanical properties of defective cyanoethynyl (2D polyaniline – C3N): A comparative molecular dynamics study versus graphene and hexagonal boron nitride

Abstract

Abstract Remarkable properties that free-standing 2D nanomaterials offer have allured academic and industrial interest in them beyond graphene. One of these materials is cyanoethynyl, which is a 2D monocrystalline carbon nitride material with a C3N stoichiometry. Investigations have confirmed its high thermal stability at elevated temperatures and ferromagnetism at low temperatures, yet very little is known about its mechanical properties. This paper reports a molecular dynamics (MD) insight into this gap. The simulations are validated against density functional theory calculations. The tensile properties of defect-free C3N sheets at/under different temperatures and strain rates are investigated. The influences of single vacancy (SV), Stone-Waals (SW), and clustered vacancy (CV) defects on these properties are also studied. The findings are compared against those reported for graphene and hexagonal boron nitride (hBN). The results show that the strength of C3N decreases with increasing temperature and/or decreasing the strain rate. They also indicate that CV defects deteriorate the mechanical properties of C3N to a greater degree than SV and SW defects. At the same defect concentration, C3N shows a lower sensitivity in its stress and strain at failure to the defects compared with graphene and hBN. For example, 3% SV can reduce the failure stress of graphene and hBN by 75% and 73%, respectively, while this reduction is 54% for C3N. For the failure strain, these reductions are 72%, 63%, and 48% for graphene, hBN, and C3N, respectively.