Carbon nanotubes (CNTs) are cylindrical tubes manufactured from one or more graphene layers in a lattice arrangement. In this article, we discuss their current and future consumer applications.
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A single-walled carbon nanotube (SWNT) diameter is typically between 0.8 and 2 nm. In comparison, the diameter of a multi-walled carbon nanotube (MWNT) ranges from 5 to 20 nm and sometimes even exceeds 100 nm.
Due to their excellent physical and chemical properties, CNTs are used in a wide range of consumer applications, including device modeling, energy storage, automobile, water purification, sporting goods, coatings, thin-film electronics, electromagnetic shields, and actuators.
Organized CNT architectures like regular sheets, yarns, and forests were produced in smaller volumes. It has even been suggested that CNTs may one day be used as the tether for a space elevator.
Various studies have recently underlined the possibility of using CNTs as building blocks for manufacturing 3D macroscopic all-carbon devices that would measure less than 1mm in all three dimensions (De Volder, Tawfick, Baughman, & A., 2013).
An innovative, radical initiated thermal crosslinking method to fabricate free-standing, macroscopic, all-carbon, porous scaffolds using CNTs as building blocks have also been reported (Machado, Lobo, Marciano, Corat, & Corat, 2015).
These scaffolds have nano-, micro-, and macro- structured pores, and the porosity can be adjusted depending on the requirements of a specific application. These all-carbon 3D architectures could be used to fabricate the next generation of supercapacitors, energy storage, high-performance catalysis, field emission transistors, biomedical implants and devices, and photovoltaics (Qian, Xie, Zou, & Zhang, 2021).
Current Consumer Applications
The most widespread use for CNTs is in structural reinforcement with other materials due to their flexibility, low weight, and high strength.
CNTs are also used in thin films and bulk composite materials (Babu, 2017). Multi-walled nanotubes (MWNTs) were first utilized as electrically conductive fillers in plastics and later to enhance fiber composites.
Some examples are hulls for maritime security boats and wind turbine blades (Liew, Yan, & Zhang, 2017). Other notable examples of CNTs are observed in strengthening sporting equipment, such as bicycle frames, baseball bats, and tennis rackets (Rajak, Pagar, Menezes, & Linul, 2019).
Water purification is another excellent example of CNTs' adsorption properties; their small surface area to volume ratio makes them ideal to be used as a membrane to filter biological contaminants, dissolved salts, and toxic chemicals from water.
Seldon Technologies, a company based in the US has developed their water filter system known as "Nanomesh Purification Technology", using CNTs. According to the company, their filter removes contaminants and pathogens like bacteria, viruses, spores, and cysts, and delivers water that exceeds or meets the USEPA Drinking Water Standard.
Future of Carbon Nanotubes in Consumer Applications
With the massive amount of research that has been done on consumer applications of CNTs, there is no doubt that the demand for commercial applications will increase drastically in the next decade. It is projected that the global CNTs market will grow from $ 5.32 billion in 2021 to $ 10.52 billion in 2028 (Fortune Business Insights, 2021).
Some notable applications to look out for in the future include solar cells and hydrogen storage:
Due to the strong UV/Vis-NIR absorption characteristics of SWNTs, a very promising application is using them in solar panels.
In 2007, the New Jersey Institute of Technology developed solar cells using a CNTs complex formed by a mixture of CNTs and carbon buckyballs to create snake-like structures.
Although buckyballs can trap electrons, they can't make them flow (New Jersey Institute of Technology, 2007). When sunlight is captured to excite the polymers, the buckyballs will grab electrons and nanotubes make the current or electrons flow.
Since then, more research has been done to create CNTs hybrid solar panels to enhance their efficiency (Fan, et al., 2017).
The hybrids are created by combining SWNTs with photo-excitable electron donors which then increases the number of electrons produced. The interaction between SWNTs and the photo-excited porphyrin generates electro-hole pairs on the SWNTs' surfaces. This phenomenon has been detected experimentally and makes a practical contribution to an increase in efficiency (Rajanna, Gilshteyn, Yagafarov, Alekseeva, & Anisimov, 2018).
Apart from CNTs being able to store electrical energy, some research has been done into using them for storing hydrogen that can then be used as a fuel source (Anikina, Banerjee, Beskachko, & Ahuja, 2019).
It is possible to condense gases inside SWNTs in high density by taking advantage of the small carbon nanotubes' capillary effects. This permits gases, especially hydrogen (H2), to be stored at a high density without it condensing into a liquid.
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Anikina, E., Banerjee, A., Beskachko, V., & Ahuja, R. (2019) Li-Functionalized Carbon Nanotubes for Hydrogen Storage: Importance of Size Effects. ACS Appl. Nano Mater Available at: doi:10.1021/acsanm.9b00406
Babu, C. R. (2017) Technical note on using CNTs as reinforcements in reinforced concrete structural elements. AIP Conference Proceedings. Available at: doi:10.1063/1.4990225
De Volder, M. F., Tawfick, S. H., Baughman, R. H., & A., J. H. (2013) Carbon Nanotubes: Present and Future Commercial Applications. Science.Available at: doi:10.1126/science.1222453
Fan, Q., Zhang, Q., Zhou, W., Xia, X., Yang, F., & Zhang, N. (2017) Novel approach to enhance efficiency of hybrid silicon-based solar cells via synergistic effects of polymer and carbon nanotube composite film. Nano Energy.Available at: doi:10.1016/j.nanoen.2017.02.003
Fortune Business Insights. (2021) Carbon Nanotubes (CNT) Market. [Online] Fortune Business Insights. Available at: https://www.fortunebusinessinsights.com/carbon-nanotubes-cnt-market-102700
Lalwani, G., Kwaczala, A. T., Kanakia, S., Patel, S. C., Judex, S., & Sitharaman, B. (2013) Fabrication and Characterization of Three-Dimensional Macroscopic All-Carbon Scaffolds. Carbon. Available at: doi:10.1016/j.carbon.2012.10.035
Machado, M. M., Lobo, A. O., Marciano, F. R., Corat, E. J., & Corat, M. (2015) Analysis of cellular adhesion on superhydrophobic and superhydrophilic vertically aligned carbon nanotube scaffolds. Mater Sci Eng C Mater Biol Appl. Available at: doi:10.1016/j.msec.2014.11.062
New Jersey Institute of Technology. (2007) New Flexible Plastic Solar Panels Are Inexpensive And Easy To Make. [Online] Science Daily. Available at: https://www.sciencedaily.com/releases/2007/07/070719011151.htm
Pang, J., Bachmatiuk, A., Yang, F., Liu, H., Zhou, W., Rümmeli , M. H., & Cuniberti, G. (2021) Applications of Carbon Nanotubes in the Internet of Things Era. Nano-Micro Letters.Available at: doi:10.1007/s40820-021-00721-4
Peng, L.-M., Zhang, Z., & Wang, S. (2014) Carbon nanotube electronics: recent advances. Materials Today. Available at: doi:10.1016/j.mattod.2014.07.008
Qian, L., Xie, Y., Zou, M., & Zhang, J. (2021) Building a Bridge for Carbon Nanotubes from Nanoscale Structure to Macroscopic Application. ACS Publications. Available at: doi:10.1021/jacs.1c08554
Rajak, D. K., Pagar, D., Menezes, P., & Linul, E. (2019) Fiber-Reinforced Polymer Composites: Manufacturing, Properties, and Applications. Polymers. Available at: doi:10.3390/polym11101667
Rajanna, P. M., Gilshteyn, E. P., Yagafarov, T., Alekseeva, A., & Anisimov, A. S. (2018) Enhanced efficiency of hybrid amorphous silicon solar cells based on single-walled carbon nanotubes and polymer composite thin film. Nanotechnology. Available at: doi:10.1088/1361-6528/aaa647
Seldon Technologies. (2022) Seldon Technologies [Online] Nanotechnology Products Database. Available at: https://product.statnano.com/company/seldon-technologies