ABSTRACT
One of the key issues in the material science of carbon nanotubes (CNTs) is to develop a methodology to solubilize/disperse them in a solvent. In this review articles, we first summarize individual solubilization of single-walled (carbon) nanotubes (SWNTs) in solvents using surfactants and polycylcic aromatic molecules, including porphyrins, deoxyribonucleic acid (DNA), and condensed polymers, as well as their optical properties. We then describe our recent approach toward the applications of novel CNT/polymer functional nanocomposites. 7.1 IntroductionCarbon nanotubes (CNTs) are made of rolled-up graphene sheets with one-dimensional extended p-conjugated structures, discovered
in 1991 by Iijima.1 They are classified into mainly three types in terms of the number of graphene layers within a CNT, that is, single-walled (carbon) nanotubes (SWNTs), double-walled (carbon) nanotubes (DWNTs), and multiwalled (carbon) nanotubes (MWNTs), which have one, two, and more than three walls, respectively. One of the key issues in the utilization of such a seminal material for basic research, together with the material applications, is to develop a methodology to solubilize/disperse them in solvents (Fig. 7.1)2-4 since as-synthesized CNTs form tight, bundled structures5 due to their strong van der Waals interaction.6 Solubilization/dispersion techniques can be categorized mainly into two methods, namely, chemical and physical modification. Solubilization/dispersion of CNTs based on physical adsorption of dispersant molecules possesses several advantages such as the ease of preparation and maintenance of intrinsic CNT properties, which show a sharp contrast with chemical modification.7-9 In this chapter, general strategies for CNT solubilization as well as the applications of solubilized CNTs are described.
