Carbon Nanotechnology : Things You Need To Know

What is Nanotechnology?

The term ‘nano’ comes from the term for ‘dwarf’ in Greek. In the metric system, the prefix nano means a factor of one billionth (10-9) and can be applied to time (nanosecond), volume (nanoliter), weight (nanogram), or length (nanometer or nm), for example. Nano refers to the length in its common use, and the nanoscale typically refers to a length from about 0.1 nm to 100 nm from the atomic level. At the nanoscale, nanostructures or nanomaterials are types of matter. To give you a basic idea about how small this is, the thickness of a single hair from your head is about 50,000-100,000 nm.

Nanotechnology needs to be called nanotechnologies: the term usually applies to fields such as biology, physics, or chemistry, to any scientific field, or to any combination thereof, which is concerned with the deliberate and regulated development of nanostructures.

Nanoscale Materials

Nanoscale materials, or nanomaterials, are materials which are within the range of nanometers with at least one appropriate length scale. Owing to the value of quantum and surface boundary effects, these materials typically have somewhat different properties from their bulk counterparts.

There are several examples we might write about nanomaterials-nanoparticles, quantum dots, nanowires, nanofibers, ultra-thin films, etc. However, one example is the element carbon, which is an example of how through nanoscale technology an 'old' material gets an exciting new life.

The Growth of Carbon Nanostructures: New Materials

The foundation of organic chemistry is carbon, a nonmetallic, strong element that exists in all organic life. It has the fascinating chemical property of being able to bond with itself, forming nearly 10 million known compounds, and a wide range of other elements. In two very distinct ways, natural carbon can occur and is known to everyone: graphite and diamond.

The current excitement among researchers about carbon nanomaterials has been triggered by three additional types of carbon discovered between the late 1980s and early 2000s: fullerenes, carbon nanotubes, and particularly graphene.

Fullerenes with sixty (C60) or more carbon atoms are spherical carbon-cage molecules. In diameter, they measure between 0.7-1.5 nm. For scientists, they are interesting because they demonstrate the peculiar properties of carbon materials. For possible medical usage, fullerenes are studied: they are effective antioxidants; unique antibiotics may also be bound to the structure to target resistant bacteria and even attack some cancer cells, such as melanoma. Some of the more heavily studied properties of fullerenes in mechanical engineering are heat resistance and superconductivity.

Fullerenes have been found to occur in interstellar dust as well as in geological formations on Earth, which are often incorrectly considered a "new type of carbon". The discovery that carbon could form solid, ordered structures globally encouraged researchers to look for other new types of carbon other than graphite and diamond. This led to carbon nanotubes( CNTs) being discovered. They are rather distinct from materials of the fullerene type and they have quite distinct properties.

Carbon nanotubes ( CNTs) are manufactured in diameter and multiple micrometers in length, ranging from single to tens of nanometers. They have excellent electronic and mechanical properties and are good thermal conductors. The tensile strength of CNTs is 6-7 times that of steel or breaking pressure. They are among the strongest and stiffest known fibres.

Depending upon their composition, CNTs may be metallic or semiconducting. The most powerful electrical conductors ever created are some CNTs, while others act more like silicon. In conjunction with the lightness of carbon nanotubes, these properties give them great potential for use in reinforced composites, nanoelectronics, sensors, and nanomechanical equipment.

CNTs are capable of having one or more walls. Single-walled CNTs have different electrical characteristics than multiwalled CNTs and are prime candidates for nanoelectronics applications. In general, the development of commercial applications has been very sluggish, mainly due to the still relatively high manufacturing costs of nanotubes of the highest quality, in particular single-walled ones. The Space Elevator-the concept that a cable-based transport device might become an alternative to rockets for launching people and payloads into space is one of the futuristic applications of carbon nanotubes.

Graphene is the newest member of the carbon nanomaterial club. Graphene, discovered only in 2004, is a flat one-atom-thick carbon layer. Current types of carbon consist of sheets of graphene, either bound on top of each other to form a solid material such as the graphite in your pencil or rolled into carbon nanotubes or folded into fullerenes (think of a single-walled carbon nanotube as a graphene cylinder).

A free-standing type of planar graphene had long been considered unlikely by physicists; the common wisdom was that such a sheet must always roll-up. The reason scientists are so excited is that two-dimensional crystals open up a whole new class of materials with novel electrical, optical and mechanical properties (it's called 2D because it spreads in just two dimensions-length and width; as the material is just one atom thick, the third dimension, height, is known to be zero).

Applications of Carbon Nanotechnology

Micron-size carbon fibres have been used for a range of uses, ranging from tennis racquets to aircraft parts, for almost 40 years because of their high strength and stiffness and lightweight reinforced polymer materials. Today, nanoscale carbon products, such as telecommunications, cars, aircraft, and space vehicles, are actively sought for a wide range of applications.

In particular, future aircraft and space vehicles are expected to have a structure built on a material with a high strength-to-weight ratio designed to withstand night, launch, and landing loads, and to perform additional functions as well. Different built-in miniaturized smart systems, including sensors, actuators, electronic and photonic instruments, will be integrated into the structure.

Carbon Nanotubes(CNTs) Structures 

Carbon nanotubes ( CNTs) consist solely of carbon atoms organized into a tubular form in a sequence of condensed benzene rings. This new artificial nanomaterial belongs to the fullerene family, the third allotropic type of carbon, along with the natural sp2 (planar) and sp3 (cubic) forms of graphite and diamond, respectively.

CNT structures are divided into two groups based on the number of layers: single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs).

Carbon Nanotubes(CNTs) and Applications

• Biomedical Applications
• In Pharmacy and Medicine
• Molecular Electronics
• Energy Storage
• Air and Water Filtration
• Electrical Conductivity
• Conductive Plastics and Adhesives
• Fabrics and Fibres
• Catalyst Supports

Potential(Future) Uses Of CNTs

They have the potential to be a cost-effective substitute for metal wires since carbon nanotubes are extremely electrically conductive. Their semiconducting characteristics make them candidates for the replacement of existing computer chips. CNTs are likely to compete with carbon fibre for high-end applications in the future, especially in weight-sensitive applications such as Kevlar. Besides, a more environmentally-friendly, flame-retardant additive to plastics has been found to be CNTs. MWNT-containing paints have also been found to minimise the bio fouling of ship hulls and prevent the attachment of algae and barnacles, making them an environmental alternative to harmful biocide-containing paints.

Researchers say their nanotube-based imaging device will take clearer, quicker images than the X-rays or CT scans of today. Other researchers have found that a more effective and lightweight catalyst for hydrogen cars than a platinum one shapes bundles of CNTs doped with nitrogen. Out of nanotube sheets, Chinese researchers produced lightweight, paper-thin speakers. These CNT speakers use the thermo-acoustic effect (similar to how lightning creates thunder) where an electric current passes through the nanotube sheets, heating and expanding the air near them, producing sound waves, unlike traditional speakers, which create noise by vibrating the surrounding air molecules. The only bendable electronics that can be made with CNTs are not these speakers.

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