A team of researchers from Finland, England, the US, Russia and Korea has reported the discovery of a novel form of nano-carbon, and named the new material ‘Nanobuds’.
Nanobuds are essentially a hybrid of single-walled carbon nanotubes and fullerene molecules, and the group that made them is led by Esko Kauppinen, a materials scientist at the Helsinki University of Technology.
The new material can be synthesised either by using particles grown in-situ via ferrocene vapour decomposition, or with pre-existing iron catalyst particles produced by a hot wire generator.
Kauppinen talks of functionalisation of the material through chemical modification: “Fullerene chemistry can be used to alter properties such as conductivity and photo-receptivity. Nanotubes in Nanobuds can be functionalised via fullerenes without chemically reacting to the nanotube grapheme.”
Nanobuds possess a number of useful properties, combining the chemical reactivity of fullerenes with the electrical, optical and mechanical properties of carbon nanotubes. Fullerene functionalisation would allow the bonding of Nanobuds to surrounding matrix materials, such as in cement to create composite concrete. Another possibility is to bond DNA to Nanobuds for direct delivery to cells in gene therapy.
A spin-off company, Canatu, has been formed to realise the market potential of Nanobuds, and a number of patents are pending on both material and processes.
Canatu hopes eventually to achieve production rates of kilogrammes per hour, but the company is currently working toward the grammes per hour rates sufficient for commercial thin-film production. “We face the typical challenges of scaling,” says Kauppinen. “However, we have particular expertise in modelling the aerosol and chemical engineering processes involved.”
Morinobu Endo, a professor at Shinshu University, Japan, comments: “This novel nano-carbon will attract lots of attention due to its novel electronic properties as well as potential in various applications (e.g., efficient emitter and multi-functional filler in nanocomposites).”
Kauppinen and Canatu have attracted much business interest in Finland, and are currently extending their search to the US business angel and venture capital markets.
Nasibulin et al. – A novel hybrid carbon material, Nature Nanotech. 2, 156 (2006) (subscription required for full article)
Bonding scenarios of fullerenes on single-walled carbon nanotubes. (a) C42 connected with a SWNT by an ester group; (b, c) C60 chemisorbed on a defect-free (8,8) SWNT by [2+2] cycloaddition (b) and [4+4] cycloaddition (c); (d, e) fullerene–SWNT hybrid structures, reminiscent of buds on a branch. The relative binding energies of individual atoms in (b–e) are reflected by colour, as shown on the right. Taken from the above paper – © Nature Publishing Group.