The carbon nanotube revolution
Carbon nanotubes (CNTs) are exactly that – cylindrical or tube-shaped materials made of carbon in the form of graphite sheets with dimensions on the nanometre (size of atoms and molecules) scale. Scientists around the world are feverishly studying CNTs. Their unique properties, including amazing strength combined with electrical and thermal conductivity, make them suited to a wide variety of applications from electronics to reinforced polymers to biosensing. CNTs can differ in length, thickness and a variety of other morphological properties. The ability to control these is the key to their usefulness in specific applications. In addition, the ability to produce CNTs on an industrial scale and at an affordable cost will be key to their commercial exploitation. European researchers initiated the ‘Carbon nanotubes for applications in electronics, catalysis, composites and nano-biology’ (Canape) project to develop scalable production methods for single-wall CNTs (SWNTs), multi-wall CNTs (MWNTs) and carbon nanofibres (CNFs) of specific dimensions. Production was based on chemical vapour deposition (CVD), the most common method for large-scale growth of CNTs. Scientists also sought to develop and scale up production of herringbone MWNTs given their potential for use as metal-free catalysts of industrial scale chemical reactions. In addition to investigation of a variety of applications based on the ability to control dimensions, researchers also conducted toxicity tests given the potential use of CNTs in biomedicine. The ability to control the dimensions of CNTs and to produce specific structures on an industrial scale will open the door to a variety of exciting applications, ranging from catalysts for hydrogen-powered cars to flexible computer screens to the proposed ‘space elevator’.
