Cyclo[18]carbon as an ultra-elastic molecular O-ring with unique mechanical properties

Recent atomic manipulation by an AFM tip created the first sp-hybridized carbon material - cyclo[18] carbon. Herein, we revealed the unique mechanical properties of cyclo[18]carbon by the first principle calculations. Under uniaxial tension, cyclo[18]carbon is ultra-elastic as demonstrated by a small Young's modulus of 0.11 TPa and a tiny specific tensile stiffness of 7.0 x 10(6) N m/kg, which are one and two orders of magnitude smaller than those of other carbon materials, respectively. The expansion and contraction of cyclo[18]carbon exhibit a relatively high specific stiffness of 9.95 x 10(8) N m/kg, and it would be broken with an energy requirement of 34.14 eV. While uniaxial tension enables the insulator-semiconductor transition of cyclo[18]carbon, expansion enlarges its energy gap. Furthermore, the strain energy was proposed as a function of bond angle and bond length for uniaxially-stretched and expanded/contracted cyclo[18]carbon respectively, which sheds light on predicting the mechanical properties of certain materials. The unique properties of cyclo[18]carbon are of great interest for its potential use as an ultraelastic molecular O-ring in nanomechanical system and molecular electronics and devices. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Recent atomic manipulation using an AFM tip has led to the creation of the first sp-hybridized carbon material, cyclo[18] carbon. This material shows unique mechanical properties, such as ultra-elastic behavior, small Young's modulus, and specific tensile stiffness, making it a potential candidate for use in nanomechanical systems and molecular electronics.