Due to the material’s exceptional properties, carbon nanotubes are great for scientific research and commercial applications. A researcher at Karlstad University explores how the atomic structure impacts the various properties of the material.
Mattias Flygare, recently qualified doctor of physics. (Image Credit: Karlstad University).
At the moment, there are too few measuring standards and no proper classification system for carbon nanotubes. “I have studied the effect of crystallinity on different properties, such as the bending stiffness and electrical conductivity of the tubes.
Mattias Flygare, Study Lead and Doctor of Physics, Karlstad University
“We know that if the tubes had a perfect atomic structure, these properties would be outstanding, however, this is rarely the case in reality. Instead, what we are seeing is that the walls of the tubes consist of a patchwork of various large “grains” with a well ordered atomic structure. The size of these crystallite grains, together with other defects, gives the material different properties,” Flygare added.
Carbon nanotubes are extremely light and thin, hollow tubes comprising carbon atoms, with walls that measure just one atom in thickness. The tube wall is similar to a sheet of graphite rolled into a cylinder, with hexagonal patterns forming the sheet.
As a result of their unique electrical, mechanical and thermal properties, carbon nanotubes deliver great potential for scientific research and commercial and industrial applications, for example in the composite materials sector, but the area of application is more extensive than that.
Grains of Perfect Patterns
I have studied the extent to which different irregularities in the atomic structure affect the properties of the material. In order to study the atomic structure, I have used our transmission electron microscope here at Karlstad University. The microscope uses a beam of electrons instead of visible light to analyze the material, which makes it possible to look at the tubes at nanometer level, that is, one billionth of a meter, which is unbelievably small.
Mattias Flygare, Study Lead and Doctor of Physics, Karlstad University
“My studies show, for example, that the properties’ dependence on the order and periodicity of the atoms inside the tube walls is not always completely linear, and there are critical points where the properties can be drastically improved simply by increasing the crystallinity a little,” Flygare stated.
This is a very remarkable outcome that reveals the necessity for more research and development of characterization approaches for carbon nanotubes so that the accurate kind of tube can be employed for the correct purpose, and to further formulate the production approaches for the tubes.
Transmission Electron Microscope
Using this method, resolution limitations of visible light can be overcome, which is around one micrometer, and down to around 100 picometers, that is, 0.1 nanometers, which is sufficiently high to resolve individual atoms. At the university, using the microscope, it is also possible to work the carbon nanotubes using a custom-built probe that can be controlled at the nanoscale.
Our electron microscope is located in house 21, but it is completely isolated from vibrations from the rest of the house. If the microscope had contact with the house, it would only take one person walking down the corridor outside the room for the vibrations to make the image blurry and unusable.
Mattias Flygare, Study Lead and Doctor of Physics, Karlstad University
Areas of Application for Carbon Nanotubes
At present, applications for carbon nanotubes can be found in several different products, and scientists continue to investigate creative new approaches for the material. Carbon nanotubes are present in numerous composite materials, for example, in sports equipment such as bicycles and tennis rackets, as a result of their ability to enhance strength and yet minimize weight.
On account of its electrical conductivity, carbon nanotubes are also beneficial in all kinds of electronics, and there are even more interesting applications on the horizon.
Journal Reference:
Flygare, M., & Svensson, K., (2021) The influence of crystallinity on the properties of carbon nanotubes. Carbon Trends. doi.org/10.1016/j.cartre.2021.100125.