Mechanical Response of Carbon Nanotubes under Molecular and Macroscopic Pressures

Abstract

High hydrostatic pressures were applied to single-wall carbon nanotubes by means of a diamond anvil cell (DAC), and micro-Raman spectroscopy was simultaneously used to monitor the pressure-induced shift of various nanotube bands. The data confirm recent results independently obtained from internal pressure experiments with various liquids, where the peak shifts were considered to arise from compressive forces imposed by the liquids on the nanotubes. It is also shown that the nanotube peak at 1580 cm-1 (the G band) shifts linearly with pressure up to 20 000 atm and deviates from linearity at higher pressure. This deviation is found to be coincident with a drop in Raman intensity for the disorder-induced peak at 2610 cm-1 (the overtone of the D* band), possibly corresponding to the occurrence of reversible flattening of the nanotubes. The independent results presented here confirm the potential of nanotubes as molecular sensors.

Tip-Enhanced Raman Scattering of Nanomaterials

“…According to previous studies [61], the G ′ band is more sensitive to the mechanical compression than the G band, and shifts by much larger degree than the G bands under compression. Thus, the G ′ band has been considered as a desirable indicator for mechanical compression.…”

“…The assignments are summarized in Table I [54]. Compared with the pure MWCNT spectrum, the G band in the SBR/MWCNT spectrum shifted to a higher wavenumber, suggesting the shrinkage of the CNTs induced by the pressure from the matrix of the polymer [56,57].…”

“…Based on previous Raman studies, Yan et al [55] concluded that the shifts of the G and the G ′ bands reflect mechanical compression of the SWCNTs by the polymer. [60,61] Figure 7(a) exhibits Raman spectra of the SWCNT/PS composites measured at nine randomly collected points (P1, P2, P3, P4, P5, P6, P7, P8, and P9) in the G band region [55]. The Raman spectra do not show a point-topoint difference in terms of band positions and relative band intensities; the G band shows only a negligible shift of < 2 cm −1 at the different points.…”

Coarse Molecular-Dynamics Analysis of Structural Transitions in Solid Materials

“…Individually, applications for CNTs include field emission sources, Lithium-ion batteries, capacitors, actuators, molecular sensors, gas and hydrogen sources, scanning probe tips, and countless electronics applications [17,18]. However, of more interest to this current study are the potential applications for nanotubes in composite materials; polymer composites in particular.…”

Carbon Nanotubes – Interactions with Biological Systems

“…High tumour accumulation of single-walled CNT (SWCNT) has been described, anticipating the possibility of further therapeutic uses . There are several studies on gas, temperature, pressure, glucose, chemical force and resonator mass sensors based on CNT Barone et al, 2005b;Collins et al, 2000;Hrapovic et al, 2004;Kong et al, 2000;Lee et al, 2007;Lin et al, 2005;Perez et al, 2005;Wood et al, 1999;Yan et al, 2007;Yang et al, 2006;Yun et al, 2007). In face of recent studies, special attention has been drawn into promising orthopaedic use of CNT for improving tribological behaviour and material mechanical properties.…”