Soluble carbon nanotubes: Fundamentals and applications

Carbon nanotubes (CNTs) have been in the forefront of nanoscience and nanotechnology because of their remarkable electronic, mechanical, and thermal properties and specific functions. CNTs have high potentials for possible applications in the fields of energy, electronics, IT, and materials. However, because of the insolubility of the nanotubes in solvents, chemical, biochemical, and biological (medical) approaches using these materials have been rather limited. Soluble CNTs in aqueous and organic systems are of interests since they may open the door in such fields. In this review article, (i) the dissolution of CNTs in water and in organic solvents by using chemical modification and physical adsorption and their applications to chemical and biological areas, (ii) separation of metallic SWNTs and semiconducting SWNTs by the combination of individual dissolution of SWNTs and the selective chemical modification, (iii) the preparation of nanotube films and fibers from dissolved/dispersed SWNTs in aqueous micelles, and (iv) CNT liquid crystal formation are summarized.