Covalent three-dimensional carbon nanotube and derived B-C-N polymorphs with superhardness and zero Poisson’s ratio

• Published in: iScience Vol. 25; no. 12; p. 105563
• Main Authors: Chen, Shuang, Hu, Meng, Liu, Lingyu, Pan, Yilong, Li, Penghui, He, Julong, Ding, Jianning
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 22.12.2022; Elsevier
• Subjects: materials science; mechanical processing; Organic chemistry; Organic chemistry; materials science; mechanical processing
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2022.105563

Carbon is one of the most versatile atoms and fosters a wealth of carbon allotropes with superior mechanical and electronic properties. A three-dimensional covalent carbon nanotube, named CCN, with a hexagonal honeycomb-like crystalline structure is proposed theoretically. CCN consists of sp3 bonded coaxially teamed (6,0) carbon nanotubes, and the tube walls possess intrinsic wrinkles, which trigger miraculous physical properties. The mechanical and thermal dynamic stabilities are confirmed, and molecular dynamics simulations indicate high temperature thermal stability up to 1500 K. CCN has an unusual cork-like zero Poisson’s ratio along the axial direction of the nanotubes, and the axial/radial stretching or compression rarely effects the radial/axial dimensions of the nanotubes. CCN is superhard with Vickers hardness of 82.8 GPa, matching that of cubic boron nitride. Substitution B and N atoms for C atoms result in superhard CCN-B12N8 and CCN-C8N12 with quasi-zero Poisson’s radio along both axial and radial directions. [Display omitted] •Stable covalent carbon nanotube with superhardness matching c-BN•Abnormally wrinkled walls result in zero Poisson’s ratio property•Radial dimensional stability under large axial tensile or compressive strain over 13%•Derived B-C-N polymorphs exhibit superhardness and zero Poisson’s ratio Organic chemistry; Materials science; Mechanical processing