Carbon nanostructures fullerenes and carbon nanotubes

Carbon atoms condense to many useful nanostructures under suitable environmental conditions in presence of some specific catalysts. Fullerene molecules and carbon nanotubes are zero and one dimensional shells made out of monatomic layer thin graphene sheet, Due to curvature Involved in otherwise graphite lattices, mixing of sp(2) and sp(3)-bondings are present in both these forms. Regular lattice symmetries of these structures have been used to understand physical, chemical and mechanical properties theoretically. Experimental techniques like STM, STS, SEM, and XRD have been employed to verify the expected behaviour in several cases. Fullerenes from single crystal solid, thin epitaxial, polycrystalline and amorphous films besides participating in numerous chemical reactions as functional molecules. Carbon nanotubes are extremely flexible and strong filaments with diameter of the order a nanometer and length extending from few to few hundred micrometers. Carbon nanotubes show strong nanocapillary action due to which a number fo metallic nanowires have been realised by filling the carbon nanotubes. Carbon nanotubes could be metallic, semiconducting or insulating depending on the structure involved. Combining these forms of carbon nanotubes in concentric form, extremely useful nanoelectronic devices and circuits are expected to be realisable. Carbon nanotubes are expected to be combined with biotechnological processes to realise nanosize robots, sensors and machines for unprecedented applications. Doing of fullerenes and carbon nanotubes is expected to provide one more dimension to their applications in realising electronic devices and systems. Besides these, there are a number of nanoencapsulants identified in the process of fabrication. A variety of nanoparticles of metals, oxide, magnetic elements have been found to be either embedded inside graphitic nanocapsules. Meal coated carbon nanoclusters also exist in such situations. In general the encapsulated species are nicely protected from environment and show superior behaviour compared to that in the bulk form. A number of composites have been formed using different forms of carbon nanostructures In appropriate matrix with unusual characteristics.