Title: Thermal properties of carbon nanotubes using characterization techniques
Abstract: Abstract Carbon nanotubes can exhibit unique ability to conduct heat. However, the effects of different factors on the thermal conductivity of carbon nanotubes are still poorly understood. Little research has been conducted to determine which parameters are important for high thermal conductivity. This study relates to the thermal properties of carbon nanotubes using characterization techniques. Carbon nanotubes were produced and characterized by scanning electron microscopy and Raman spectroscopy. The effects of different factors on the thermal conductivity of carbon nanotubes were investigated to understand the characteristics of thermal transport in the nanostructured material. The objective is to gain insight into the fundamental characteristics of thermal transport in carbon nanotubes. Particular emphasis is placed on the dependence of thermal conductivity on different factors, with an attempt to improve the heat conduction properties for carbon nanotubes. The results indicated that a single-walled carbon nanotube can be described as a long tube formed by wrapping a single graphene sheet into a cylinder with diameter of about one nanometer, the ends of which are capped by fullerene cages. The sidewalls of carbon nanotubes are made of graphene sheets consisting of neighboring hexagonal cells. Three different types of single-walled carbon nanotubes are distinctly characterized, named zigzag, armchair, and chiral. These structural variations result in differences in electrical conductivity and mechanical strength. Multi-walled carbon nanotubes are concentrically aligned single-walled carbon nanotube assemblies with different diameters. The distance between adjacent shells is about 0.34 nanometer. Multi-walled carbon nanotubes differ from single-walled carbon nanotubes not only in their dimensions, but also in their corresponding properties. The specific thermal conductivity decreases with increasing bulk density. The bulk density may be controlled to produce carbon nanotube films with high thermal conductivity. As for thermal properties, carbon nanotubes outperform diamond as the best thermal conductor. Applications of carbon nanotubes are aimed to make use of their unique properties to solve problems at the nanoscale.