Critical Investigation of Defect Site Functionalization on Single-Walled Carbon Nanotubes

Abstract

SWNTs produced by the HiPco technique were purchased from Unidym ® , Inc. (Lot no. R1912).Reagents and solvents were purchased as reagent-grade from Fisher Scientific Ireland Ltd, or Sigma-Aldrich Ireland and used without further purification.TGA analyses were performed on a PerkinElmer Thermogravimetric Analyzer Pyris 1 TGA. The method used for performing TGA measurements is as follows: 5 minute isothermal step at 30 °C (to S3 equilibrate the sample); heat from 30 °C to 100 °C at a rate of 10 °C min -1 ; 20 minute isothermal step at 100 °C (to ensure evaporation of the solvents); heat from 100 °C to 900 °C at a rate of 10 °C min -1 .FT-IR spectra were measured in the solid state on a PerkinElmer FT-IR Spectrometer Spectrum 100 with a universal ATR sampling accessory (diamond/ZnSe crystal). The spectra were recorded at 256 scans with a 4 cm -1 resolution.Micro-Raman scattering measurements were carried out at room temperature in the backscattering geometry using RENISHAW 1000 micro-Raman system equipped with a CCD camera and a Leica microscope. An 1800 lines mm -1 grating was used for all measurements, providing a spectral resolution of ~ 1 cm -1 . As an excitation source the He-Ne laser with 633 nm excitation with variable powers was used. Measurements were taken with 20 seconds of exposure time and 4 accumulations. The laser spot was focused on the sample surface using a 50x objective with short-focus working distance. Raman spectra were collected on numerous spots on the sample and recorded with Peltier cooled CCD camera.Only one spectrum was collected per spot. The intensity ratios I D /I G were obtained by taking the peak intensities after a baseline correction. The data were collected and analyzed with Renishaw Wire and GRAMS software.XPS measurements were performed in a VERSAPROBE PHI 5000 from Physical Electronics, equipped with a Monochromatic Al Kα X-Ray source with a highly focused beam size which can be selected from 10 µm to 300 µm. The energy resolution was 0.6 eV. For the compensation of built up charge on the sample surface during the measurements a dual beam charge neutralization composed of an electron gun (~1 eV) and the Argon Ion gun (≤10 eV) was used.UV-Vis Absorption spectra were recorded on a Perkin Elmer UV/Vis Spectrometer Lambda 35 after 1 cycle, with an interval of 1 nm, slit width of 2 nm and scan speed of 240 nm min -1 . Emission spectra were taken in a HORIBA Jobin Yvon Fluorolog-3 Spectrofluorometer equipped with a 450 xenon CV lamp after 1 cycle, with slit width of 10 nm and integration time 0.1 s.

Molecular Dynamics Simulation Study on the Mechanical Properties and Fracture Behavior of Single-Wall Carbon Nanotubes

“…A review (Krasheninnikov & Banhart, 2007) on the engineering of CNTs and other carbon materials with electron ion beams discus the recent advancements in this respect. Defects can serve the purpose of grafting functional groups directly at the defect site (Canto et al, 2011). Addition reaction is most favorable in the position of Stone-Wales defects at the carbon-carbon double bond.…”

Comparative temporal analysis of multiwalled carbon nanotube oxidation reactions: Evaluating chemical modifications on true nanotube surface

“…These procedures have been shown to be inefficient in the removal of oxidation debris adhered to CNT surface, which may make up almost a quarter of the sample mass [9]. More recent studies have employed basic solution reflux followed by neutralization to remove oxidation debris through the repulsion created between the negative charge on the CNT surface and the impurities [10][11][12][13][14][15][16]. Several studies have investigated changes in nanomaterials due to the application of this protocol.…”

Surface-enhanced Raman scattering spectra of radial breathing and G band modes in functionalised nanotubes

“…One of the challenges in applying SWCNTs to create devices is that these nanotube structures form metastable suspensions rather than true solutions. One way to overcome this is functionalization of the SWCNT [12][13][14][15][16][17][18][19][20]. Functional groups covalently attached to the nanotube sidewalls prevent the aggregation of SWNTs into bundles and enhance their solubility/dispersibility in organic solvents.…”

“…Altering the properties and functionality of SWCNTs through the addition of covalently bounded molecular groups is a well-developed technology [12][13][14][15][16][17][18][19][20]. Raman spectroscopy (including SERS) provides a potential method to characterise functionalised SWCNTs.…”