On the Mechanical Properties and Fracture Patterns of Biphenylene-Based Nanotubes: A Reactive Molecular Dynamics Study

Carbon-based materials have garnered significant attention since the groundbreaking synthesis of graphene. The exploration of novel 2D carbon allotropes has led to the discovery of materials with intrinsic properties distinct from graphene. Within this context, the biphenylene network (BPN) was successfully synthesized. In this study, we used molecular dynamics (MD) simulations with the Reactive Force Field (ReaxFF) to delve into the thermomechanical properties and fracture patterns of biphenylene-based nanotubes (BPN-NTs) exhibiting armchair (AC-BPN-NT) and zigzag (ZZ-BPN-NT) chiralities. Throughout the longitudinal deformation process, we observed significant morphological transformations preceding the structural fracture of the system. These transformations unfolded in distinct inelastic phases. In both cases, AC- and ZZ-BPN-NT, stress accumulation in four-membered rings led to the creation of octagonal structures; however, in AC, this occurs in the fracture region, subsequently causing the presence of nanopores. On the other hand, for ZZ-BPN-NT, stress accumulation in the rectangular rings occurred in bonds parallel to the deformation, with elongated octagonal structures. The Young’s modulus of these nanotubes ranged from 746 to 1259 GPa, with a melting point of around 4000 K. Our results also explore the influence of diameter and curvature, drawing comparisons with BPN monolayers.