Carbon nanotubes: From molecular to macroscopic sensors

Abstract

The components that contribute to Raman spectral shifts of single-wall carbon nanotubes ͑SWNT's͒ embedded in polymer systems have been identified. The temperature dependence of the Raman shift can be separated into the temperature dependence of the nanotubes, the cohesive energy density of the polymer, and the buildup of thermal strain. Discounting all components apart from the thermal strain from the Raman shift-temperature data, it is shown that the mechanical response of single-wall carbon nanotubes in tension and compression are identical. The stress-strain response of SWNT's can explain recent experimental data for carbon nanotube-composite systems.

Raman bands of double‐wall carbon nanotubes: comparison with single‐ and triple‐wall carbon nanotubes, and influence of annealing and electron irradiation

“…11 G-band shape changes are reported while doping, 19 applying pressure 21 and changing the surrounding medium. 23 The influence of the environment on the G band might be unexpected at first. But all carbon atoms of SWCNTs are on the surface and, as a result, the G band is sensitive to the environment.…”

“…Large shifts (20 cm 1 ) of the G 0 2D band in SWCNTs have been reported in the literature. 23 We compare spectra of CNTs in methanol and air when using a low laser power (Fig. 1).…”

“…22 The second-order spectrum of the D band, G 0 2D , has been used to probe the effects of the environment on SWCNTs. 23,24 It has been suggested that the two features contributing to the D band are due to the inner and outer tubes, 25 leading, consequently, to a splitting of the G 0 2D band. Its temperature and pressure dependence are useful to extract information on the influence of the tube environment.…”

Interfacial energy between carbon nanotubes and polymers measured from nanoscale peel tests in the atomic force microscope

“…Many researchers have shown that the addition of a small volume fraction of CNTs to various polymers can improve the bulk modulus of the composite materials such as epoxy [5], polyimide [6], polyethylene [7], methyl-ethyl ethacrylate [8], or polyvinyl alcohol [9]. Additionally, the large electrical and thermal conductivities of carbon nanotubes have lead to the creation of unique nanocomposites that can quickly dissipate electrostatic charges [10] or withstand high temperatures with minimal mechanical degradation [11]. Since the first reported work on CNT-reinforced polymer nanocomposites materials [12], they have found widespread application in automotive, aerospace, defense, sporting goods, infrastructure, and medical sectors [13][14][15].…”

Resistive–conductive transitions in the time-dependent piezoresponse of PVDF-MWCNT nanocomposites

“…Many researchers are applying this phenomenon using various materials systems with a range of electrically conductive fillers. The materials systems, which are being investigated in this study, are thermoplastics, [1][2][3][4][5][6][7][8][9][10][11][12] thermoset resins, 13,14 and cement. 15 Of the various types of nanofillers, carbon nanotubes (CNTs) are the dominant choice when conductivity is necessary, because they provide high strength and modulus at low concentration.…”