Mechanical properties of single-walled penta-graphene-based nanotubes: A DFT and Classical molecular dynamics study

Abstract

Abstract Membranes of carbon allotropes comprised solely of densely packed pentagonal rings, known as penta-graphene, exhibit negative Poisson’s ratio (auxetic behavior) and a bandgap of 3.2 eV. In this work, we investigated the structural stability, mechanical and fracture properties of nanotubes formed by rolling up penta-graphene membranes, the so-called penta-graphene nanotubes (PGNTs). Single-walled PGNT of three distinct configurations: ( n , 0 ) , and two types of ( n , n ) (here called α and β ) were studied combining first-principles calculations and reactive molecular dynamics simulations. Our results showed Young’s modulus values of 680–800 GPa, critical strain of 18–21%, ultimate tensile stress of 85–110 GPa, and Poisson’s ratio values ranging from - 0.05 to - 0.3 (auxetic behavior). During stretching at room temperature, we observed a transition from β - ( n , n ) to α - ( n , n ) PGNT near the critical strain. Fracture of PGNTs starts at the bonds that are mostly aligned to the stretching direction and after nanotube radial collapse.