Carbon nanotubes: Novel architecture in nanometer space

I describe here the basic structure of nanometer size tubules of graphitic carbon with the aid of high resolution transmission electron microscopy. The distribution of pentagons and heptagons on the hexagonal lattice of curved graphene sheets results in numerous morphologies in the closed cylindrical geometry of the tubules. The arrangement of hexagons on the tube surfaces follow helical patterns and the band structure is reported to change accordingly resulting in interesting electronic properties. The defect free structure of these nanotubules have been predicted to result in mechanically one of the strongest material in nature. All the more, the internal cavities of the tubules have been recently utilized for filling in different inorganic materials creating unique nano-composites. I review the recent developments on carbon nanotubes and discuss what potential awaits this material for possible future applications, considering the fact that bulk amounts of purified material is now available.