Carbon Tubes Research Paper

Carbon nanotubes (CNTs) were first observed by Radushkevich and Lukyanovich in 1952 and later in 1976 Oberlin et al observed the single (or double) walled carbon nanotubes[1,2,3]. In 1991 Iijima was the first scientist to discover CNTs, who described the multiwalled carbon nanotubes (MWNTs) during the preparation process of C60 carbon molecule fabrication after random event during the test of a new arc evaporation method [4]. In 1993 two separate works from Iijima et al. and Bethune et al. described the growth process of single walled carbon nanotubes (SWNTs) [5,6].

Carbon nanotubes (CNTs) are characterized as a graphene sheet rolled-up to form a tube, like a single-walled tube (SWCNT). When two or more concentric tubes are placed one into another, multi-walled carbon nanotubes (MWCNTs) is formed.

Carbon consists of two allotropes which are are diamond and graphite. In diamond, there are four available electrons in which each carbon bonds with the nearest neighbours, which forms a tetrahedral structure (sp3). Such arrangement is called a covalent bonding and is known to be of high strength which is the reason of the high strength in diamond. Since all the electrons are involved in the bonding, they do not interact with light, hence they possess low electrical and high thermal conductivity properties. In graphite, the in-plane bonds of the electrons form a hexagonal structure (sp2), which is even stronger than the sp3 in diamond. Since graphite (planes) interact weakly by van der Waals bonding with the different layers which makes them capable to slip easily with respect to each other. Hence the graphite has softness, high electrical conductivity and lubricating properties. A single plane of graphite is known as a graphene, which contains a flat hexagonal arrangement of carbon atoms with very strong in-plane