Carbon nanotubes are allotropes of carbon which take the form of cylindrical tubes. They have novel properties that make them potentially useful in a variety of applications in nanotechnology, optics, electronics, and other fields of materials science. Carbon nanotubes are categorized into two main types: single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs).
Single-walled Carbon Nanotubes
SWCNTs are produced through the Arc- discharge process. They have a purity of about 95 to 98wt% and include roughly 92 to 95wt% of carbon nano particles. SWCNT has a diameter of about 0.7 to 2nm and forms a bundle measuring 8nm. It does not require any separate refinery process.
Characteristics and Applications of Single-walled Carbon Nanotubes
SWCNTs have excellent mechanical strength with superior heat and electric conductivity. They have high crystallinity and aspect ratio together with excellent Arc- discharge element characteristics.
SWCNTs are used in chemical sensors, nano biomaterial, conductive heating film, conductive transparent electrode, conductive nanoink, nano device, and display (backlight, flat lamp and field emitter).
Multi-walled Carbon Nanotubes
MWCNT is produced by means of thermal CVD process and does not need a separate refinery process. Its diameter ranges from 10 to 30nm and has a purity of at least 95%. MWCNT are suitable for polymer and CNT-metal composites.
Characteristics and Applications of Multi-walled Carbon Nanotubes
Similar to SWCNTs, MWCNTs have excellent mechanical strength with superior heat and electric conductivity. They also have high specific surface area, high crystallinity, and high length-to-diameter ratio.
Carbon nanotubes are used in a wide range of application such as chemical sensors, conducting paints, energy storage, and composite materials (ESD, heat exchanger, reinforced material and EMI shielding).