Deformation Behavior of the Raman Radial Breathing Modes of Single-Wall Carbon Nanotubes in Composites

2003 ◽  
Vol 791 ◽  
Author(s):  
Marcel Lucas ◽  
Robert J. Young
Keyword(s):  
Carbon Nanotubes ◽  
Tight Binding ◽  
Low Frequency ◽  
Intensity Variation ◽  
Single Wall Carbon Nanotubes ◽  
Energy Separation ◽  
Resonance Theory ◽  
Electronic Density ◽  
Single Wall Carbon ◽  
Radial Breathing Modes

ABSTRACTRaman spectroscopy is a technique widely used to study the vibrational modes of carbon nanotubes. The low-frequency Radial Breathing Modes (RBMs) are frequently used to characterize carbon nanotube samples. We report a Raman spectroscopic study on the strain-induced intensity variations of the RBMs of Single-Wall Carbon Nanotubes (SWNTs) in epoxy/SWNT composites. The RBM intensities have been found to vary significantly over a range of strain between -0.3% and 0.7%. The trend (increase or decrease) as well as the magnitudes of the intensity variation depends on the nanotube diameter and its chirality. Using tight-binding calculations, we have shown that these intensity variations can be explained entirely by resonance theory. Electronic density of states calculations confirm that the energy separation between the Van Hove singularities shifts with strain. The nanotubes are thus moved closer or further away from resonance, causing the intensity variations. It is demonstrated that through the use of resonance theory, a tentative chirality can be assigned to each type of SWNT from knowledge of its RBM position and the effect of strain upon the RBM intensity, thus determining its entire structure.

NMR Investigation of n-Alkylamine Self-Organization Along the Sidewalls of Single-Wall Carbon Nanotubes (SWNTs)

2004 ◽  
Vol 858 ◽  
Author(s):  
Sang-Yong Ju ◽  
Marcel Utz ◽  
Fotios Papadimitrakopoulos
Keyword(s):  
Carbon Nanotubes ◽  
Density Of States ◽  
Single Wall Carbon Nanotubes ◽  
Aliphatic Chain ◽  
Community Based ◽  
Electronic Density ◽  
Single Wall Carbon ◽  
Bulk Separation ◽  
The One ◽  
Differential Solubility

Single wall carbon nanotubes (SWNTs) have drawn considerable attention from the scientific community based on their potentially unique 1-D electronic and optical properties as well as mechanical properties. These characteristics result from the one dimensional quantum wire structure of CNTs, which have the spike-like van Hove singularities (vHs) in the electronic density of states. The detailed shape of the density of states function depends sensitively on CNT type semiconducting (sem-) versus metallic (met-)), diameter and chirality. Using the preferential affinity of amines towards sem -SWNTs, our group has been able to attain bulk separation by type based on a differential solubility of SWNTs according to the amine organization interaction on the nanotube surface. It has been argued that stable dispersions of sem -SWNTs with surfactant-amines originate from the organization of the aliphatic chain along the nanotube sidewalls, along with a small amount of zwitterions. The separation of sem-enriched SWNTs assisted by octadecylamine (ODA) had been depicted in the form of either small amount of zwitterionic interaction between carboxylic acid groups of acid-purified SWNTs or the physisorption on the SWNTs sidewall, leaving met -SWNTs in the precipitate.

THE ROLE OF POTENTIAL FUNCTIONS IN THE MECHANICAL BEHAVIOR OF THE SINGLE WALL CARBON NANOTUBES

2012 ◽  
Vol 11 (03) ◽  
pp. 1240009 ◽  
Author(s):  
KEKA TALUKDAR ◽  
APURBA KRISHNA MITRA
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Interatomic Potential ◽  
Tight Binding ◽  
Flow Region ◽  
Potential Functions ◽  
Dynamics Simulation ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon

Carbon nanotubes have been identified as the promising agents in reinforcing composite materials to achieve desired mechanical properties. In this study, three different types of single wall carbon nanotubes (SWCNTs) are subjected to molecular dynamics simulation to investigate their mechanical properties taking different interatomic potential functions. With unmodified Brenner's 2nd generation potential, a brittle fracture for all the SWCNTs is observed. But in tight-binding approach, the chiral and armchair SWCNTs exhibit somewhat extended plastic flow region before failure. With unmodified Brenner's potential, high tensile strength and ductility are observed for the armchair and chiral tubes. Y value of these two tubes is less than 1 TPa but more than 1 TPa for a zigzag tube. Much decrease of tensile strength and strain are noticed when we apply smoothing of the Brenner's potential at cut-off region. Failure stresses are dropped to much lower values for the three tubes. Ductility of the armchair and chiral tubes are also affected considerably by the choice of potential. Applying smoothing in the cut-off region to conserve the energy, the results show better agreement with the experimental findings.

scholarly journals Low-Frequency Current Fluctuations in Individual Semiconducting Single-Wall Carbon Nanotubes

Nano Letters ◽  
2006 ◽  
Vol 6 (5) ◽  
pp. 930-936 ◽  
Author(s):  
Yu-Ming Lin ◽  
Joerg Appenzeller ◽  
Joachim Knoch ◽  
Zhihong Chen ◽  
Phaedon Avouris
Keyword(s):  
Carbon Nanotubes ◽  
Low Frequency ◽  
Single Wall Carbon Nanotubes ◽  
Current Fluctuations ◽  
Single Wall Carbon ◽  
Frequency Current
Sign in / Sign up

Export Citation Format

Share Document