9 research outputs found
Method for functionalizating carbon naontubes utilizing peroxides
A method for functionalizing the wall of single-wall or multi-wall carbon nanotubes involves the use of acyl peroxides to generate carbon-centered free radicals. The method allows for the chemical attachment of a variety of functional groups to the wall or end cap of carbon nanotubes through covalent carbon bonds without destroying the wall or endcap structure of the nanotube. Carbon-centered radicals generated from acyl peroxides can have terminal functional groups that provide sites for further reaction with other compounds. Organic groups with terminal carboxylic acid functionality can be converted to an acyl chloride and further reacted with an amine to form an amide or with a diamine to form an amide with terminal amine. The reactive functional groups attached to the nanotubes provide improved solvent dispersibility and provide reaction sites for monomers for incorporation in polymer structures. The nanotubes can also be functionalized by generating free radicals from organic sulfoxides
Observation of Alignment Effects in High-Field Proton NMR Spectra of Hydrogenated Fullerenes:Ā Evidence for Residual Anisotropic DipoleāDipole Couplings
Cytotoxicity and variant cellular internalization behavior of water-soluble sulfonated nanographene sheets in liver cancer cells
Highly exfoliated sulfonated graphene sheets (SGSs), an alternative to graphene oxide and graphene derivatives, were synthesized, characterized, and applied to liver cancer cellsĀ in vitro. Cytotoxicity profiles were obtained using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, WST-1[2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, and lactate dehydrogenase release colorimetric assays. These particles were found to be non-toxic across the concentration range of 0.1 to 10 Ī¼g/ml. Internalization of SGSs was also studied by means of optical and electron microscopy. Although not conclusive, high-resolution transmission and scanning electron microscopy revealed variant internalization behaviors where some of the SGS became folded and compartmentalized into tight bundles within cellular organelles. The ability for liver cancer cells to internalize, fold, and compartmentalize graphene structures is a phenomenon not previously documented for graphene cell biology and should be further investigated
Physical removal of metallic carbon nanotubes from nanotube network devices using a thermal and fluidic process
Overcoming Catalyst Residue Inhibition of the Functionalization of Single-Walled Carbon Nanotubes via the BillupsāBirch Reduction
The
BillupsāBirch Reduction chemistry has been shown to
functionalize single-walled carbon nanotubes (SWCNTs) without damaging
the sidewalls, but has challenges in scalability. Currently published
work uses a large mole ratio of Li to carbon atoms in the SWCNT (Li:C)
to account for lithium amide formation, however this increases the
cost and hazard of the reaction. We report here the systematic understanding
of the effect of various parameters on the extent of functionalization
using resonant Raman spectroscopy. Addition of 1-iodododecane yielded
alkyl-functionalized SWCNTs, which were isolated by solvent extraction
and evaporation, and purified by a hydrocarbon wash. The presence
of SWCNT growth catalyst residue (Fe) was shown to have a strong adverse
effect on SWCNT functionalization. Chlorination-based SWCNT purification
reduced the amount of residual Fe, and achieve a maximum I<sub>D</sub>/I<sub>G</sub> ratio using a Li:C ratio of 6:1 in a reaction time
of 30 min. This result is consistent with published literature requiring
20-fold mole equivalents of Li per mole SWCNT with a reaction time
of over 12 h. This new understanding of the factors influencing the
functionalization chemistry will help cut down material and process
costs, and also increase the selectivity of the reaction toward the
desired product