The journal Carbon reported that specialists from Japan’s Waseda University managed to produce the forest, reaching a height of 14 cm.
Chinese specialists had earlier produced individual nanotubes of up to 50 cm in length, but never beyond a height of 2 cm. Such individual nanotubes are of less practical value when applied to industry.
A “forest” is generally built on the basis of silicon using, as a catalyst, iron with a covering of aluminium oxide.
But construction of higher structures was inhibited by the rapid deterioration of the catalyst. The Japanese specialists extended the life of the forest and prevented the deterioration by adding gadolinium.
In addition, the scientists placed the catalyst in a chamber where a process of cold sedimentation from the steam phase occurred. It was then heated to 750 degrees C with constant additions of atoms from vaporised iron and aluminium. The catalyst was kept in order for 26 hours, enabling the scientists to achieve the record 14 cm height.
Carbon nanotubes are tubes from carbon atoms with the thickness of a wall made up of single atoms. They are vital in several branches of industry, among them optics, electronics, medicine and water purification.
The of nanotubes can help create extremely light and durable materials. They can improve the properties of nearly any material, improving not durability but also electrical conductivity and heat conductivity.
A forest of nanotubes is used in the process of artificial photosynthesis which may be used to supply cheap energy from the sun and water.
One of the specialists developing this system is Peidong Yang, professor of energy and chemistry at the University of California, Berkeley and a laureate of the Global Energy Prize.
The building of nanotubes in this instance proved more durable, of better quality and cleaner. The academics believe that this discovery gives rise to optimism on the possibility of widespread use of nanotubes in industry. Maintaining the catalyst in working condition could be used in petrochemicals, the growing of crystals, energy and other applications.