Characterization and functionalization of carbon nanotubes

Carbon nanotubes have emerged as promising building blocks for various molecular devices because of their unique structure and potentially useful properties. Despite extensive efforts made in the past, many potential applications of this exotic material have still not been realized in part because of processing and manipulation difficulties. Chemical functionalization is anticipated to facilitate applications of carbon nanotubes by changing their surface properties and providing a method for attachment of other functional molecules.; A detailed study of carbon nanotube characterization and functionalization is described in this thesis. Some preliminary application data are also presented. Chapter 2 describes characterization of several different carbon nanotube structures by electron microscopy. These images show that carbon nanotubes can form a variety of morphologies under different synthetic and functionalization conditions. In Chapter 3, a rapid analytical method is presented, that can provide quantitative information about amine groups on functionalized carbon nanotubes. In Chapter 4, an approach to labeling carbon nanotubes with a fluorescent dye is shown. This chemical approach allows us to see carbon nanotubes more easily and better understand the properties of carbon nanotubes. In the second part of this chapter, we demonstrate a self-assembly approach to construct a reversible photo-active system using functionalized single walled carbon nanotubes and zinc porphyrin building blocks. A potential application of this system as a photo-energy conversion system is anticipated. Besides covalent chemistry, we also describe a non-covalent approach to functionalization of carbon nanotubes in Chapter 5. This approach is able to modify the surface of carbon nanotubes, which allows better dispersion in aqueous or organic solvents. Finally, we present some promising results about field emission properties of the functionalized carbon nanotubes. The experimental data shows that functionalized carbon nanotubes can be ideal electron emitters for making field emission devices.