These cylinders of precisely ordered carbon atoms are finding uses in a wide variety of industries due to their unique mechanical, electrical and thermal properties. Jànos B. Nagy, a chemist who is Professor Emeritus at Namur University, Belgium, talks about his passion for CNT whose work led to the creation of Belgian CNT manufacturer Nanocyl.
Historically, why did industries use CNT?
The interest of industrial companies is related to applications of nanocomposite materials. For example, one very interesting application is the development of composite membranes for water purification and gas absorption, whilst electronic applicationsare more suitable for future massive solutions such as batteries.
How widespread are CNTs in industry today?
Applications of composite materials are well developed. But research on composite membranes with carbon nanotubes as nanofibers is not yet quite ready to be applied, mainly due to the absence of low cost material. The results obtained could be used in two or three years for massive industrial applications such as in industrial energy storage devices called electrochemical capacitors. In terms of European development, Belgium is a major area of CNT production and Germany is more focussed on applications.
Could you give a few examples of the variety of applications available today?
CNT are used as fillers in advanced composite materials made of polymers, metal and ceramic matrices that could be used, for example, for fuel lines in automobiles. These present greater strength, toughness and damping of vibrations. In the case of thin film composites, they can also be used as coatings with special properties, including as flame barriers for electrical cables and for eco-friendly ship hull coatings. Also, they are used in probes in microscale applications like Micro-Electro-Mechanical Systems (MEMS) technologies or as scanning probe microscope tips and electrical interconnects in circuits and on chips.
Other applications of nanotubes are found in fillers in composites for electrostatic discharge and electromagnetic shielding, in batteries and supercapacitors, in fuel cell electrodes and catalyst supports, in displays and as X-Ray emitters.
What are the main technological challenges that need to be overcome to meet the needs of industry?
The main problem in nanocomposites is achieving the homogeneous dispersion of the CNTs in a matrix, often made out of polymer. The challenge in the field of electronic applications is the unstable electrical performance of CNT based equipment. This occurs in LCD displays, for instance, thus limiting the size and resolution of the screens. Another application, such as hydrogen storage in CNT, will need many years of research in order to be suitable for industrial applications.
What needs to improve in order to deal with possible hazards linked to the use of nanotechnology in consumer goods?
A better management of the reagents during the CNT synthesis is required to achieve a more uniform dispersion of nanotubes. CNT are not dangerous for potential consumers if the applications are carried out correctly; e.g. through monitoring of CNTs during or after manufacturing. They do not offer risk if they are not dispersed into the environment, namely in the air, water and ground.
25 January 2013
by Hywel Curtis