**2.2 Structure/properties of CNT**

There are numerous mechanisms available to build up structures occluded with various characteristics. The sp2 nature of carbon hybridization constructs a layered pattern of arrangement with weaker plane bonding of Vander Waals forces at the outside and strong forces at inner plane bounds. Few numbers of concentric cylinders were equipped with regular spacing of interlayers that are located around central hollow section and demonstrated as multi walled CNTs **Figure 5**. In general, the real time spacing of MWCNTs contain interlayer spacing in range of 0.35–0.40 nm. The inner diameter of multi-walled CNTs can even range from 0.40 nm to few nanometers [28]. Outer diameter can exist up to 25 nm. The tips on both sides were closed and protruding ends were capped using dome shaped half width fullerene molecules. Axial molecules can exist up to few centimeters. The primary function of half width fullerene molecules is to aid in shutting down the tubes at both the ends. Whereas SWCNT can exist up to 4 nm. Length is up to micrometer range. Such arrangement is organized in a hexagon shape so as to develop a crystal [29].
