HIPCO

SWNTs (HiPco, Carbon Nanotechnologies Incorporated) were shortened by ultrasonication with a probe-type sonicator in mixed acids (H2SO4 and HNO3) under ice-cooling. After diluting the mixture with water (MiliQ), the shortened SWNTs were purified by filtration through a PTFE membrane filter (pore size 1 pm or 0.2 pm) or by chromatography (Sepadex G-50). 

Little progress was made after these preliminary findings until 2004, when Lam et al. investigated the pulmonary toxicity of three types of SWNTs (raw HiPCO SWNTs, purified HiPCO SWNTs, and Ni-catalyzed arc discharge SWNTs) instilled in mice [58]. It was found that all three SWNT samples induced dose-dependent lung lesions and interstitial inflammation after 7 days. These lesions persisted and worsened after 90 days. 

SWNTs HiPCO HaCaT Time-dependent cytotoxicity [25]... 

SWNTs HiPCO HaCaT Oxidative stress (ROS production, NF-kB activation) [45]... 

SWNTs HiPCO (30wt% Fe vs. 0.23 wt% JB6 P + EpiDerm FT Unpurified SWNTs free radical generation, [46]... 

SWNTs HiPCO (10wt% Fe) HaCaT Reduced cell proliferation [26]... 

Aminohexanoic acid HiPCO HEK Dose-dependent cytotoxicity [31]... 

Phenyl-functionalized SWNTs HiPCO ([Pg.199]

SWNTs Pulmonary toxicity HiPCO (30wt% Fe) Mice Topical exposure 5d Oxidative stress Skin thickening Inflammation [46]... 

SWNTs-[(DOTA) (AF488) (AF680)] HiPCO Mice... 

Raw SWNTs or purified HiPco SWNTs or Arc-SWNTs (0.1 or 0.5mg/mouse) Male mice B6C3Fj Intratratracheal instillation 7 and 90 days Induced dose-dependent epithelioid granulomas Lam et al. (2004)... 

Proper solution electrochemical experiments on pristine SWNTs were only possible after the recent discovery of an innovative way to form thermodynamically stable solutions of unmodified and uncut SWNTs.17,60 Upon reduction with alkali metals, SWNTs produce polyelectrolyte salts (Scheme 9.16) that are soluble in polar organic solvents without the use of sonication, surfactants, or functionalization. Polyelectrolyte SWNT salts were obtained by reacting arc-discharge samples (a-NT) or HiPco samples (h-NT) with different alkali metals (Na, K). 

The typical voltammetric curve for a solution of SWNTs in organic solvents displays a continuum of diffusion-controlled current, with onset, in both the negative and the positive potential region, that depends on the nanotube average diameter and ultimately on the NT preparation technique. In fact, SWNTs prepared according to the arc-discharge method display an anticipated onset with respect to HiPco ones... 

Scheme 9.18 Top Plots of optical absorption intensity as a function of wavelength and electrode potential in the Sii region for K[h-NT]. In all plots, raw electrochemical data, that is, uncorrected for ohmic drop, are referenced to SCE. Bottom Chirality map displaying the average standard potentials associated to each SWNT. HiPco SWNTs are located inside the red line, while arc-discharge SWNT are inside the blue line. Starred values were extrapolated from the linear fitting equations given in the text. (See the color version of this Scheme in Color Plates section.)...

Abstract Raman spectra of film HiPCO carbon single-walled nanotubes (SWNTs) with... 

SWNTs were prepared by high-pressure CO decomposition over the Fe catalyst (HiPco method [13]) at Carbon Nanotechnologies Inc. Houston, Texas, USA. The raw sample was purified by controlled thermal oxidation in air followed by sonication in HC1. The purity estimated by elemental analysis, TGA, XRD and TEM gave in result 99% content of SWNT in the samples studied [4],... 

The Raman spectrum of HiPco SWNT obtained at the He-Ne laser excitation of 1.96 eV has three characteristic regions four bands in the low frequency region at 100-300 cm 1 (radial breathing mode (RBM)), two intensive bands at 1500-1600 cm 1 (tangential mode (G-mode)) of the spectrum and D mode (near 1300 cm"1) [14-18], At He-Ne laser excitation 4 intensive bands (RBM) are observed in Raman spectra of HiPCO nanotubes, corresponding to SWNTs of different diameters and chirality. 

Single-wall carbon nanotubes (SWNTs) can be prepared by laser-vaporization of a graphite source. A newer process uses carbon monoxide as the source of the carbon and is called the HiPco process. The catalyst is generated in situ from iron carbonyl. The SWNTs from the HiPco process are characterized by a smaller diameter and exhibit greater reactivity with organic reagents. 

Derivatized products such as alkyl-, aryl-, alkoxyl- and amino-nanotubes and cross-linked nanotubes are obtained (Scheme 1.2). F-SWCNTs prepared by the HiPCO process exhibited a higher degree of alkylation using alkyllithium reagents than fluorinated SWCNTs from the laser-oven method. Dealkylation occurred at 500 °C. 1-Butene and n-butane were formed during the thermolysis... 

HiPCO-SWCNTs were oxidized in a UV-03 gas-solid interface reaction and subsequently assembled on a rigid oligo(phenylenethynylene) self-assembled monolayer (SAM). In a chemical assembly , based on condensation between the carboxylic acid functionalities of the 03-oxidized SWNTs and the amine functionalities of the SAMs, SWCNT-amides were formed in ordered arrays [116]. 

Basic studies on diazonium-CNT chemistry led to two very efficient techniques for SWCNT derivatization solvent-free functionalization [176] and functionalization of individual (unbundled) nanotubes [175], With the solvent-free functionalization (Scheme 1.26), heavily functionalized and soluble material is obtained and the nanotubes disperse in polymer more efficiently than pristine SWCNTs [176], With the second method, aryldiazonium salts react efficiently with the individual (unbundled) HiPCO produced and sodium dodecyl sulfate (SDS)-coated SWCNTs in water. The resulting functionalized tubes (one addend in nine tube carbons) remained unbundled throughout their entire lengths and were incapable of reroping. [175],... 

Reductive alkylation of carbon nanotubes using lithium and alkyl halides yields sidewall-functionalized nanotubes soluble in common organic solvents. Billups group prepared dodecylated SWCNTs from raw HiPCO tubes using lithium and dodecyl iodide in liquid ammonia and demonstrated the occurrence of exten-... 

Addition of carbanions - syntheses of tert-butyl-H-SWCNTs and of tert-butyl-SWCNTs In a nitrogen-purged flask, equipped with a gas inlet and a pressure compensator, 20 mg of HiPCO tubes (1.7 mmol of carbon) was dispersed in 50 mL of anhydrous benzene. To this dispersion 2.5 mL of a 1.7 M solution of tert-butyllithium (4.25 mmol) in hexane were added dropwise over a period of 10 min. Subsequently, the suspension was additionally stirred for 1 h at room temperature and the SWCNT dispersion turned into a black homogeneous solution. The solution was stirred for a further 1 h and subsequently quenched by the addition of... 

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