| Single-walled carbon nanotubes (CNTs) are a promising material for many nanoscale electronic applications. CNTs are able to carry very high currents, and are very sensitive to the environment around them making them ideal for sensing on a very small scale. However, to date no significant commercial applications have been achieved because of difficulties in sorting the nanotubes by type, placing them on a target site and interfacing them into a device such as a field-effect transistor (FET) that could be used as a sensor. CNTs are well dispersed in water by DNA, and form a stable hybrid structure, DNA-CNT. This hybrid can be sorted according to CNT length and chirality using Ion-Exchange Chromatography (IEC), providing a valuable route to CNT purification. This thesis centers on helping explain how the purification process works and on developing ways to place the DNA-CNT from an aqueous suspension on a target site to be used in a device.; Purification is done by IEC, which separates species partly on the basis of their electrostatic properties in solution. ABAQUS(TM) finite-element models of DNA-CNT electrostatics are reported which help explain, for example, how metallic CNTs screen the charge on DNA more than semiconducting ones. Other applications of Poison- Boltzmann solution electrostatics theory, including the electrostatic field near a metal electrode, are also reported. Understanding electrostatic fields near an electrode plays a role in dielectrophoretic placement of CNTs.; Experimental results are reported on Meniscus Alignment, a way of placing and orienting DNA-CNT on top of a self-assembled monolayer (SAM) and kinetics models are developed to help explain the process. Meniscus Alignment is shown to be a versatile technique which can produce finely tuned deposition densities and spatially varying alignment patterns. Finally, a Capillary Electrophoresis (CE) study of the DNA-CNT is reported. This study found that CE has some capacity for sorting DNA-CNT by chirality. The mobility measurements made are compared to mobilities of single- and double-stranded DNA and used to infer aspects of the poorly understood DNA-CNT structure. |
