title: Tensile Characterization of Single-Walled Carbon Nanotubes with Helical Structural Defects.
abstract: Recently, evidence was presented that certain single-walled carbon nanotubes (SWNTs) possess helical defective traces, exhibiting distinct cleaved lines, yet their mechanical characterization remains a challenge. On the basis of the spiral growth model of SWNTs, here we present atomic details of helical defects and investigate how the tensile behaviors of SWNTs change with their presence using molecular dynamics simulations. SWNTs have exhibited substantially lower tensile strength and strain than theoretical results obtained from a seamless tubular structure, whose physical origin cannot be explained either by any known SWNT defects so far. We find that this long-lasting puzzle could be explained by assuming helical defects in SWNTs, exhibiting excellent agreement with experimental observation. The mechanism of this tensile process is elucidated by analyzing atomic stress distribution and evolution, and the effects of the chirality and diameter of SWNTs on this phenomenon are examined based on linear elastic fracture mechanics. This work contributes significantly to our understanding of the growth mechanism, defect hierarchies, and mechanical properties of SWNTs.
authors: Sensor System Research Center, Korea Institute of Science and Technology, Seoul 136-791, Korea.
authors: Young I
authors: YI
authors: Jhon
authors: Sensor System Research Center, Korea Institute of Science and Technology, Seoul 136-791, Korea.
authors: Chulki
authors: C
authors: Kim
authors: Sensor System Research Center, Korea Institute of Science and Technology, Seoul 136-791, Korea.
authors: Minah
authors: M
authors: Seo
authors: Sensor System Research Center, Korea Institute of Science and Technology, Seoul 136-791, Korea.
authors: Woon Jo
authors: WJ
authors: Cho
authors: Center for Opto-Electronic Conversion System, Korea Institute of Science and Technology, Seoul 136-791, Korea.
authors: Seok
authors: S
authors: Lee
authors: Sensor System Research Center, Korea Institute of Science and Technology, Seoul 136-791, Korea.
authors: Young Min
authors: YM
authors: Jhon