They are allotropes of carbon with a cylindrical nanostructure. These cylindrical carbon molecules have remarkable properties that make them potentially useful in many applications in nanotechnology, electronics, optics and other fields of materials science. They come in both single-walled and multi-walled forms. Their structure and composition give them very unique physical and chemical properties.
Structure and Properties
They are composed solely of carbon atoms arranged in hollow tubes that are bonded together in hexagonal shapes. A single-walled Carbon Nanotubes (SWNT) can be imagined as a single layer of graphite rolled up into a seamless cylinder. It has a diameter close to a nanometer, which is approximately 50,000 times thinner than a human hair. Multi-walled carbon nanotubes (MWNT) consist of multiple rolled layers (concentric tubes) of graphite.
The atomic structure of it determines their excellent mechanical and electrical properties. They are about 100 times stronger than steel at about one-sixth the weight of steel. They also have an exceptionally high Young’s modulus (tensile stiffness), typically around 1 TPa. They offer extraordinary electrical conductivity and can carry an electric current density 1000 times greater than copper. Both single and multi-walled they can demonstrate either metallic or semiconducting behavior depending on their helicity and diameter.
Potential Applications
The unique properties of them make them ideal candidates for many high-tech applications. Some potential application areas are mentioned below.
Electronics and Sensors – They can be used as nanoscale wires, transistors that can operate at the molecular level. They can also be used to produce ultra-sensitive chemical and biological sensors. Some scientists have even built nanotube-based devices that are 1,000 times faster than current chips.
Composite Materials – By combining it with other materials like plastics, ceramics, and metals, their natural properties can be enhanced to form lightweight yet very strong composite materials of the future. For example, adding just 0.1% of carbon nanotubes can triple the tensile strength of cement.
Energy Storage – Their supercapacitors could be used for energy storage, achieving energy densities 10–100 times that of electrolytic capacitors. Lithium-based batteries using single-walled nanotubes as anodes could increase storage capacities by 10 times that of graphite anodes.
Electronics Displays – Adding them to LCD displays can produce the next generation flexible, rollable and low power consuming electronic paper and displays. Their reflectivity, luminous efficiency, and lifetime make them ideal for lighting applications.
Biomedical Applications – Carbon nanotubes are promising for drug delivery systems, tissue engineering scaffolds, prosthetics and retinal implants due to their small size and strength. Researchers have shown they are well-tolerated in the body in many studies.
Major Challenges for Commercialization
While they have generated enormous interest across different fields, several challenges remain for their large-scale commercial applications:
Mass Production – Existing manufacturing processes still cannot provide high-quality, chirality-controlled nanotubes in bulk quantities needed for commercial use. New scalable growth techniques are required.
Purity Control – As-produced nanotubes contain metal catalyst residues and other impurities that affect conductivity. Their complete removal is difficult but needed for many applications.
Solubility Issues – They tend to bundle or aggregate due to strong van der Waals interactions between tubes. Making them soluble and dispersible isn’t easy.
Reliability Issues – Long term reliability and failure analysis are lacking for it based devices and structures despite intensive research. More testing data is needed.
Health and Safety – Toxicity aspects of it, especially for human health and the environment, need thorough evaluation before widespread adoption.
Standardization – Lack of standards for measuring and specifying carbon nanotube properties poses challenges for mass commercial and industrial use.
While there are formidable challenges remaining, the remarkable properties of carbon nanotubes continue to excite the scientific community and drive innovation. As our ability to manipulate matter at the nanoscale improves, they have the potential to transform entire industries and our daily lives through revolutionary technologies in the decades to come if these challenges are addressed. Advancements in scalable growth, purification methods, property manipulation and testing reliability will determine the timeline for their large scale adoption as the wonder material of the future.
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it.