Carbon Nanotubes Features and Characteristics

Single Walled Nanotubes (SWNT) has some different mechanical and electrical characteristics than Multi-walled Carbon nanotubes  (MWNT).

• Electrical
• The Single Walled Nanotubes has electrical excellent properties. For a given nanotube if (n=m) the nanotube is metallic; if n-m is a multiple of 3, then the nanotube is a semiconductor. On molecular levels in the metallic form nanotubes can carry electrical current that is significantly higher than metals as copper.
•  The Multi-walled Nanotube doesn’t show the electrical properties of the single walled Nanotube.
• Thermal
• Carbon Nanotubes is a very good thermal conductor along the tube. Its predicted to transmit up to 6000 watts /meter /Kelvin at room temperature with very good temperature stability up to 750 deg C in air.
• Defects
• Can and will affect the material properties. They come in to types atomic vacancies and Stonewall defect. With high levels of defects tensile strength can be reduced by 85%
• Crystallographic defects, which can result in, lower conductivity.
• Crystallographic and Stone Wales defects can also affect thermal properties by reducing the thermal conductivity. 
• Toxicity
• Testing for toxicity of this heterogeneous material is on going at this time. There are many parameters that can affect Carbon nanotubes affect on living tissue. Some of them but not all the factors are: Structure surface area, size distribution, surface area and purity of the sample.
• Under some conditions Carbon nanotubes can cross membrane barriers, which suggests that if raw material reach the organs they can induce harmful effects such as inflammatory and fibrotic reactions.
• Further research is required but the preliminary results demonstrate that under certain conditions like involving chronic exposure, carbon nanotubes can pose a serious risk to human health
• Kinetic
• Multi-walled carbon nanotubes, which are multiple concentric nested CNT with in one another. They exhibit telescoping properties where the inner tubes can slide almost frictionless within each other. This creates an atomically perfect linear or rotational bearing.
• Strength
• Carbon nanotubes have excellent tensile strength and elastic modulus
• A multi walled carbon nanotube in terms of tensile strength with a cross section of 1mm has been tested to showing the ability to hold 63000kg. This equates to a specific strength of 48,00 kN•m •kg‾¹ which is significantly higher than high strength steel at 154 kN•m•kg‾¹.
• CNT because of there hollow structure is not as strong under compression, torsional or bending stress.
• Comparison of Mechanical Properties of some of the forms of CNT