2. NanotubesNanotubes
Definition: A flat layer of graphite rolledDefinition: A flat layer of graphite rolled
into a tube.into a tube.
Physicist Alex Zettl, shown here with a model of a carbon nanotube
Classification according to the number of layers. There is another classification based on the configuration. Armchair: lines of hexagon are parallel to the main axis Zigzag: lines of hexagons are perpendicular to the main axis Chiral: lines of hexagons are diagonal to the main axis. Sort of spiraling around an imaginary axis.
Tensile strength: the capacity to resist tension for a carbon nanotube is more than 500 times that one of steel. Two reasons: Carbon atoms are covalently bonded. One long molecule that avoids weak spots ( junctions) Elasticity: The young’s modulus (force required to bend a material) is more than five times greater than for steel. Nanotubes can be bent 120 degrees and snap back. Density: 6 times lighter than steel Thermal conduction: is 10 times greater than for silver. Heat is transmitted by the vibration of the covalent bonds and the stiffness improves the flow of heat. Electrical conduction: superconductors because electricity flows almost without resistance through the nanotube. There are no atoms to bump into. Less energy is wasted as heat Functionalization: capacity to change properties by bonding new atoms. Carbon has 4 places where it can bond different atoms. Luminescence: anotubes are able to emit light Self-assembly: they form on their own in the presence of a catalyst Chemically inert: they will not prompt reactions in other materiasl.
*Improving semiconductors: The high conductivity could be useful in making electric paint, absorbing static, storing energy or replacing chips' silicon circuits. Are potentially handy for cooling confined spaces like PCs. Reduce the size of electronics *High Resolution displays: Magnetic Resonance Image, TV prototype by Texas-based Applied Nanotech in conjunction with japanese electronic firms. Nanotubes could be used in optical fiber due to its luminescence. *Medicine: Tiny sensors and implants to provide automated monitoring and deliver treatment where is needed.
*They could be used to replace copper wires reducing the size and increasing the electrical conductivity. *They could help create super-strong plastics, and superstrong composites, yet lighter for the the military equipment, construction of armors, etc. *Carbon Nanotubes may store huge amounts of hydrogen ; therefore, they are been used in the development of new sources of energy.