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Continuous growth of carbon nanotube films
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Continuous growth of carbon nanotube films
Due to their unique structures and superior mechanical, electrical, and other physical properties, carbon nanotubes (CNTs) have shown great potential as building blocks for a variety of novel high-performance materials. CNT films, which can be synthesized via CVD methods as well as wet processing approaches, have been proven to be promising for using as composite reinforcements, electric conductors, thermal management materials, etc. Floating catalyst chemical vapor deposition (FCCVD) is a simple and environmentally friendly process among the preparation methods of CNT films.Get more news about carbon nanotube film seller ,you can vist our website!
It has the advantages of low cost and mass production, and is very helpful for the large-scale preparation of high-performance CNT films. In this review, we first briefly discuss development of FCCVD technology. Then the CNT growth mechanism in the FCCVD process and the relationship between key process parameters and quality/structure property of CNT film are discussed in-depth. The unique properties and the state-of-the-art applications of the CNT films in composite and some other application fields are overviewed in detail. Finally, the opportunities and remaining challenges toward its real applications are prospected.
In the practical applications, macroscopic assemblies constructed with individual CNTs are the most common forms which lead to much higher processability, including fibers, films/membranes, and foams.[3] In spite of these excellent properties mentioned above for the individual CNTs, the CNT assemblies generally exhibit depressed performance as compared to individual ones due to the limited length of CNTs, the defects/impurities, imperfect alignment/staking of CNTs, and so on.[19], [20] Among the above-mentioned CNT assemblies, CNT films/membranes are one of the most extensively researched area, which can offer better reproducibility by the statistical averaging of enormous number of CNTs. Their unique properties such as flexibility, optical transparency, together with high conductivity, strength, and surface area, making the CNT films suitable for the applications of composites, electrodes for energy devices, electromagnetic shielding layers, transparent conductive films (TCFs), sensors, electrical heater, and so on.
There are two primary strategies to fabricate CNT films, including wet processing and dry processing strategies. The wet processing method generally involves surfactant adsorption and high-energy processes like ultrasonic dispersion and ultracentrifugation, which will lead to residual impurities on CNT surface, defects in the tube and length-shortening of the tubes, thus degrading the performance of the CNT films.The dry-processing strategy mainly includes two approaches. The first one is drawing the CNT films from a vertically aligned CNT forest grown on a substrate.[28] The second one is deposition the CNT films directly from a floating catalyst chemical vapor deposition (FCCVD) system.The former one involves two independent main stages, namely the growth of the vertically aligned CNT array and the film drawing from the array, and this multistep process results in more complexity and lower yield. In contrast, FCCVD direct deposition of CNT films has higher yield and cost-effectiveness, and can be easily scaled up for mass production. For convenient comparison, the advantages and disadvantages of FCCVD to other methods for the preparation of CNT films are clearly listed in Table 1. Moreover, the FCCVD process offers the good control over the structure and morphology of CNTs and bundles by critical tuning of growth and collecting parameters, including length, diameter, electrical type, chirality, alignment, thickness, and so on.The illustration of the unique properties and typical applications of the FCCVD CNT films is shown in Fig. 1.