Single walled carbon nanotubes: Suspension in aqueous/surfactant media and chirality controlled synthesis on surfaces
Moore, Valerie C.
Smalley, Richard E.
Doctor of Philosophy
Single walled carbon nanotube (SWNT) researchers have many obstacles to overcome before SWNTs become commercially applicable including two equally important but separate issues: suspending pristine, individual SWNTs in water and chirality controlled synthesis. The first part of this thesis describes how to suspend, analyze, and manipulate individually suspended SWNTs in twenty four different surfactants and polymers. The second part of this thesis explains how to attach a metal nanoparticle to the open end of a short SWNT and seamlessly grow the same chirality SWNT. Suspending pristine, individual SWNTs in water is critical for some composite material applications and any biological application. This research characterizes the spectral properties and the ability to suspend individual SWNTs for over twenty surfactants and polymers. In addition, methods for concentrating and purifying the SWNT suspensions are detailed. Finally, three examples applications of these SWNT suspensions in material and biomedical application are described. Being able to synthesize chirality-specific SWNTs in bulk quantities is critical for chirality specific SWNT applications. Currently, the problem lies with the initial SWNT nucleation; there is no control. The method for controlling SWNT chirality proposed in this thesis is a templated growth model using an existing SWNT as the template. A new catalyst particle is attached to the end of a SWNT creating a SWNTcat. During growth the carbon addition is directed through the catalyst to the existing SWNT resulting in seamless, chirality consistent growth. To test the models validity, a proof of concept was carried out on surfaces where the growth could be monitored by atomic force microscopy (AFM). The SWNTcats were prepared with a variety of catalysts in several solvents. Straight, seamless growth of the SWNTcat was seen with a variety of growth conditions proving this is a viable route to large scale synthesis of chirality-specific SWNT production.