Enrichment of Metallic Single-Walled Carbon Nanotubes with Simultaneous Purification by Nitric Acid Treatment

Aluminum nitride‐single walled carbon nanotube nanocomposite with superior electrical and thermal conductivities

“…Conductivity grade water was produced from a quartz double distillation plant (AQDD.XL.RSH, Bhanu, India). A detailed procedure for the enrichment of the tubes with metallic variety has been described earlier . Briefly, pristine SWCNTs were digested with nitric acid at 50°C for 20 hours.…”

“…After the cycle was repeated several times, the final stable sol was dried at 140°C slowly to form a highly reflecting black paper labeled as M‐SWCNT. The enrichment of metallic SWCNTs (68%) in the product were confirmed from the analyses of Raman and optical spectra and the dc conductivity measurements . FTIR spectra of the M‐SWCNT samples have been obtained (Perkin Elmer, Spectrum 100) to look for the surface chemistry of the tubes.…”

“…This paper describes the development of AlN‐SWCNT composite, a new material, in which purified SWCNTs enriched with metallic varieties (M‐SWCNT) have been used as dispersoids in AlN ceramic matrix for investigation on the change of its electrical as well as thermal properties. The method of purification and simultaneous enrichment of metallic tubes consist primarily of controlled treatment with HNO 3 . The electrostatic attraction between –COO ̅ groups on the surface of SWCNTs and AlOH 2 + present on the surface of AlN particles in protic solvents helps in better bonding of the SWCNTs with the AlN particles under controlled colloidal procedure adopted in the present protocol.…”

“…No work could be cited in the literature on the separation of the tube varieties before incorporating them into ceramics. Simultaneous purification and enrichment of the SWCNTs with the metallic varieties (~70%) could be possible by controlling the acid reflux method . However, dispersion of SWCNTs in any solvent is one of the critical tasks for making composites and several unique processes like carboxylation and freeze granulation have been adopted in earlier studies to obtain homogeneous microstructure both in ceramics as well as metal matrices .…”

Wide dynamic range enrichment method of semiconducting single-walled carbon nanotubes with weak field centrifugation

“…Out of Gaussian fits to the absorbance of the raw dispersions we deduced the mean diameters and the diameter distribution as follows5152: HiPco SWCNTs (1.17 nm ± 0.13 nm), Plasma SWCNTs (1.30 nm ± 0.10 nm) and Arc discharge SWCNTs (1.44 nm ± 0.12 nm). The as-produced SWCNTs were dispersed in an aqueous solution containing 2 wt% of PAE by horn sonication for 1 h at 100% amplitude (Dr. Hielscher UP200s) starting with 0.5 wt% of raw nanotube material in a total of 50 g of dispersion.…”