The applications of carbon nanotubes

Tackling the biggest challenges of our time sometimes involves harnessing the power of some of the smallest particles: nanoparticles. Here we delve into the fascinating world of carbon nanotubes (CNTs), a marvel of nanotechnology with the potential to revolutionize numerous industries.

What are carbon nanotubes?

Carbon nanotubes are cylindrical, hollow structures composed of carbon atoms arranged in a hexagonal lattice. CNTs can be single-walled (SWCNTs) or multi-walled (MWCNTs), with the different configurations offering unique properties based on their size and structure. The diameter of a carbon nanotube is measured on the nanoscale, yet they can have extreme aspect ratios where their length extends into the millimeter range. The exceptional tensile strength of CNTs, combined with their unique thermal and electrical conductivities, could mean they become invaluable in numerous research areas and applications¹.

New frontiers in electronics

Over the last 30 years, a prominent trend in electronics has been the progressive shrinking of everyday electronic devices whilst their computing power and complexity has increased. The drive for increasingly small and powerful devices has been a primary motivation for the electronics industry to embrace nanotechnology, including CNTs. The appeal of carbon nanotubes goes beyond their size. For example, CNTs exhibit exceptional electrical conductivity making them ideal candidates for developing high-performance transistors² that can promise faster processing speeds and greater energy efficiency compared to traditional silicon-based devices. Moreover, the mechanical strength of CNTs could be advantageous when developing flexible electronics or components that undergo repeated stress and strain.

Advancements in materials science

One of the most exciting applications of carbon nanotubes lies in their ability to reinforce composite materials³. Incorporation of CNTS into polymers, metals, and ceramics, produces composites that are significantly stronger, more durable, and lighter than their conventional counterparts. These enhanced materials have vast applications, including aerospace components, automotive parts, and sports equipment, where there is often a fine balance between weight and performance. Similarly, the mechanical strength of CNTs is being exploited to develop wear-resistant coatings which improve the longevity and functionality of various products. These coatings are particularly valuable in the electronics industry where they can also exploit the electrical and thermal properties of CNTs to protect delicate components.

Revolutionizing energy storage

The energy sector is undergoing a momentous transformation fueled by the increasing adoption of renewable energy sources and the ongoing shift towards electrification. One of the main challenges that accompanies this transformation is the ever-increasing demand for energy storage. Carbon nanotubes could fast become key to this revolution due to their ability to store and conduct energy. Because of their lattice like structure for such small particles, CNTs have a large surface area enabling them to store more charge than traditional capacitors. This behavior has led to CNTs sometimes being described as ‘super-capacitors’⁴. Furthermore, in battery technology, the use of CNT-enhanced electrodes has been shown to facilitate rapid ion transport which significantly improves the capacity, charge/discharge rates, and therefore, efficiency, performance and lifetime of batteries.

Medical discoveries and biosensors

CNTs have shown remarkable potential in the fields of medicine and biosensing again thanks to their unique physical properties and importantly, biocompatibility. CNTs can be functionalized to carry specialized biomolecules for targeted drug delivery thanks to their nanoscale and high surface area⁵. Furthermore, CNTs used for drug delivery can be developed to release the specialized therapies in a controlled manner in response to specific stimuli. The implications of these advancements will mean drugs can be delivered directly to diseased cells or tissues, enhancing treatment efficacy while minimizing side effects.

Another exciting application area within medicine for CNTs is biosensing and imaging. Much like their use in targeted drug delivery, CNTs can be tagged with contrast agents or fluorescent markers to enable high-resolution imaging of cellular and molecular structures. Moreover, their unique conductive properties can be harnessed to develop sensors capable of detecting biomarkers in blood and other biological fluids.

Purification and filtration

In water treatment, CNTs excel at removing contaminants, heavy metals, and pathogens, providing access to clean and safe water⁶. Their high surface area and high porosity is ideally suited to adsorb contaminants such as heavy metals, organic pollutants, and bacteria. These properties extend their capabilities to be used in air filtration systems where CNTs can capture harmful particles from our atmosphere to help improve air quality and reduce the health risks associated with air pollution.

Conclusions

The potential of carbon nanotubes is vast and transformative. From electronics and materials science to energy storage and medicine, CNTs are at the forefront of innovation. Some of the greatest challenges for scientific advancement include targeted drug delivery for increasingly complex diseases, electrification and battery development, reducing and mitigating widespread pollution and facilitating the renewable energy transition. All these challenges can be addressed with the clever use of CNTs.

At Malvern Panalytical, we are excited to be part of this technological revolution, developing solutions that allow us insight into the incredible properties of CNTs to address the challenges of today and leverage particles and material science to create a healthier and sustainable future.

Explore all our analytical solutions for carbon nanotube research on our website here.

Prefer to speak to an expert? Get in touch with our specialist team today!

• How XRF can help carbon nanotubes become the supermaterial of the future
• Carbon and Carbon Nanotube Characterization by Nanoparticle Tracking Analysis
• Characterization of Single Wall Carbon Nanotubes (SWNTs) by combining Dynamic Light Scattering and Raman Spectroscopy

References

1. Harris, P. J. F. Carbon Nanotube Science: Synthesis, Properties and Applications. (Cambridge University Press, 2009).
2. Franklin, A. D., Hersam, M. C. & Wong, H.-S. P. Carbon nanotube transistors: Making electronics from molecules. Science 378, 726–732 (2022).
3. Coleman, J. N., Khan, U., Blau, W. J. & Gun’ko, Y. K. Small but strong: A review of the mechanical properties of carbon nanotube–polymer composites. Carbon 44, 1624–1652 (2006).
4. Yu, D. et al. Scalable synthesis of hierarchically structured carbon nanotube–graphene fibres for capacitive energy storage. Nature Nanotech 9, 555–562 (2014).
5. Jha, R., Singh, A., Sharma, P. K. & Fuloria, N. K. Smart carbon nanotubes for drug delivery system: A comprehensive study. Journal of Drug Delivery Science and Technology 58, 101811 (2020).
6. Das, R. et al. Multifunctional carbon nanotubes in water treatment: The present, past and future. Desalination 354, 160–179 (2014).