Metin Atmaca 030080007 10th week definitions part 2

2. CNT (Carbon Nano Tubes) (Nanotechnology):

There is no previous definition.

Definition:

Over the last few years there has been an increasing trend to further miniaturize the sensors/actuators from the micro to the nano scale. This is due to some outstanding properties that these nano-scale materials can offer over conventional bulk materials. One such nano-scale material is the carbon nanotube (CNT). From their unique electronic properties and thermal conductivities higher than diamond to mechanical properties where the stiffness, strength and resilience exceed any current material, carbon nanotubes offer tremendous opportunities for the development of fundamentally new material systems. In particular, the exceptional mechanical properties of carbon nanotubes, combined with their low density, offer much scope for the development of nanotube-reinforced composite materials. The potential for nanocomposites, reinforced with carbon nanotubes, having extraordinary specific stiffness and strength properties, represent tremendous opportunities for applications in the 21st Century.

CNTs, due to their superior properties, have immense potential for use in many structural applications. A single layer of CNTs can achieve 50 times the tensile strength of conventional steel [53], while the mass density of CNTs is only 1/6 that of steel. These properties highlight the promising role of CNTs in applications involving nanomaterials and nanodevices. Theoretically, the tensile modulus and strength of a graphene layer can reach up to 1 TPa and 200 GPa, respectively.

In addition to the exceptional mechanical properties associated with carbon nanotubes, they also possess superior thermal and electric properties. They are thermally stable up to 2800 C in vacuum, have a thermal conductivity about twice as high as diamond and an electric-current-carrying capacity 1000 times higher than copper wire. These exceptional properties have been investigated for devices such as field-emission displays, scanning probe microscopy tips and microelectronic devices.

(Varadan, V. K., Smart Material Systems and MEMS: Design and Development Methodologies, p. 35)