Fabrication, functionalization, and dispersion of carbon nanotubes

Discovery of carbon nanotubes (CNTs) was beginning of a revolutionary path for material scientists. CNTs extraordinary properties made this wonder material an important alternative for scientists in all fields; although utilizing CNTs were not as simple as synthesizing them. Ever since the discovery, numerous platforms for synthesis of CNTs have been investigated. Depending on the necessity of the application in which CNTs are exploited different quality, yield, chirality, size, and properties are required. Nowadays the fabrication process mostly relies on arc discharge, laser ablation and chemical vapor deposition (CVD). One of the major drawbacks in exploitation of CNTs is their tenancy to aggregate due to the weak van der Waals forces present as a result of sp2 hybridization of carbon atoms. Due to the extraordinary mechanical, electrical, optical, chemical, physical, biological, and other features of CNTs, scientists began to work on different methods to overcome aggregation during utilization of CNTs. Dispersion of CNTs has been done via several functionalization processes. Each of these techniques has their own functionality. Functionalization of CNTs depends on two central techniques, covalent and noncovalent modifications, which are essential, to achieve desired characteristics that can be applied in wide range of applications. Therefore, in this chapter we will try to explain the CNTs fabrication techniques as well as the methods that have been utilized to increase the purity and dispersion of CNTs.