About Us
NanotubesSWCNT Technology
Nano-C’s process technology offers the following advantages:
An exothermic production process. Nano-C’s process uses premixed combustion of gas after introduction of catalyst precursors with a cold gas mixture.
Selective production of SWCNT. Nano-C has consistently demonstrated that the control of its process leads to exclusive and selective production of SWCNTs.
Continuous product collection. Continuous techniques at our disposal include conventional bag-house filtration and continuous collection in liquids with no atmospheric exposure.
Purification. Existing purification techniques for removing metallic catalyst particles can be used, whether batch or continuous.
Scale and scalability. Our nanotube operation ran at 1.0-1.5 g/day in Q1. In Q2 ’06, a larger burner was installed which reaches 10 - 15 g/8-hour day. The resulting equipment is sufficiently large to demonstrate the scalability of the technology and to provide samples to interested partners and customers. Combustion at higher pressure is also a promising route to achieve increased SWCNT productions rates without a major scale-up. Preliminary work has shown that with doubled flow rates and pressures, the amount of collected material is about two-fold higher.
Reproducibility. Reproducibility of the nanotube-production process is ensured by rigorous control of all process parameters. Quality control of all batches is conducted by Raman spectroscopy which allows for the assessment of the diameter of SWCNTs and of the relative abundance of the D-band indicating the level of impurities or other symmetry-breaking effects. Product analysis of multiple batches at nearly identical conditions has revealed very similar Raman spectra in all cases. All spectra showed a very narrow distribution of the radial-breathing mode (RBM) with a pronounced peak at about 220 cm-1 which corresponds to a tube diameter of 1.1 nm. The D-band, appearing near a wave number of 1350 cm-1, was very weak in all cases with typical ratios between the RBM and D-bands of > 15.
Multiple degrees of freedom in operating conditions. Current control points include the following conditions of operation: pressure, type & particle size of catalyst, fuel-oxygen ratio, dilution with inert gas, cold gas velocity.
Process extensions. Among the possibilities are: the use of electric fields between the burner surface (nanotube generation) and the collector to potentially achieve greater alignment of carbon nanotubes; in situ processing of substrates; and liquid phase collection among others.