Modified carbon nanotubes

It is well known that carbon nanotubes possess outstanding electrical and mechanical properties, and if they are modified these carbon nanotube (CNT) modified properties can be improved or other novel characteristics can appear. In addition, these modified carbon nanotubes, being different from their pure counterparts, now require additional studies to assess their toxicity and biocompatibility. Generally speaking, carbon nanotubes can be classified as single-, double- or multi-walled, and each type can be modified; For example, these tubular structures can be doped with foreign atoms, incorporate structural defects, and/or be functionalized with different molecules. These local modifications greatly modify their electronic and chemical properties, and can be understood by using a variety of microscopy and spectroscopy techniques. In Sect. 6.1, we describe the general concepts and synthesis for the main doping types. In Sect. 6.2, we focus on the different types of defects that can be introduced into nanotubes so as to modify their physicochemical properties. Section 6.3 discusses the categories of nanotube chemical functionalization and their resulting effects. The electrochemical properties of modified carbon nanotubes are an important topic that needs further investigation, and Sect. 6.4 reviews the latest advances in this area. The characterization techniques mainly used to study modified carbon nanotubes are reviewed in Sect. 6.5. Some applications of modified carbon nanotubes are described in Sect. 6.6. Finally, aspects of the toxicity and biocompatibility of modified carbon nanotubes are presented in Sect.6.7. The chapter finally provides an outlook and perspectives in the field.