CNT Nano Dispersion

CNT Nano Dispersion List

Carbon nanotube (CNT), also known as Bucky tube, is a kind of one-dimensional quantum material with special structure (the radial size is nanometer, the axial size is micron, and both ends of the tube are basically sealed). Carbon nanotubes are mainly composed of hexagonal carbon atoms to dozens of layers of coaxial circular tubes. The distance between layers is fixed, about 0.34nm, and the diameter is generally 2-20 nm. According to the different orientations of carbon hexagons along the axis, carbon hexagons can be divided into three types: sawtooth type, armchair type and spiral type. Among them, spiral carbon nanotubes are chiral, while zigzag and armchair carbon nanotubes are not chiral. As one-dimensional nanomaterials, carbon nanotubes are light in weight, perfectly connected in hexagonal structure, and have many abnormal mechanical, electrical and chemical properties. CNT nanodispersion refers to adding carbon nanotubes into a certain solvent to disperse into a stable dispersion.

Figure 1. Carbon nanotube.

Applications:

• Catalyst: Carbon nanotube carrier has unique and stable structure and excellent surface properties after functionalization, so it is suitable to be used as catalyst carrier. In addition, because carbon nanotubes have the advantages of hollow structure, appropriate pore size distribution, large pore size, large specific surface area, controllable lumen structure, high hardness, high strength, high thermal stability and good corrosion resistance, so it has a broad application prospect in the field of catalyst carrier. It has been applied in oxygenation catalyst, fuel cell catalyst and dilute hydrocarbon polymerization catalyst carrier.

Figure 2. Schematic of the fabrication process of the NiFe/N-CNT catalyst and the flexible ZAB based on this catalyst.

• Sensors: Carbon nanotubes have unique one-dimensional quantum confinement properties, so they have attracted wide attention in the field of science. Carbon nanotubes have high strength, good elasticity and chemical stability, and can realize the transformation from metal properties to semiconductor properties at nanometer scale. Carbon nanotubes with semiconductor properties are suitable for the construction of nanoscale sensors.
•  Composites: The average Young's modulus of carbon nanotubes is 1.28 TPa and the average bending strength is 14 GPa, which is better than other carbon fibers, so carbon nanotubes have great potential in strengthening polymer materials. Carbon nanotubes with unique structural characteristics can be used as good fillers for polymers to further improve the mechanical and electrical properties of polymers.

Production:

• Physical dispersion: One way to disperse carbon nanotubes is to shorten the length of carbon nanotubes. Compared with the longer carbon tubes, the shorter carbon tubes are not easy to be entangled and agglomerated into aggregates. Therefore, the mechanical method mainly depends on the shear force to break the carbon nanotubes from the defects to reduce the length of carbon nanotubes, so as to prepare stable dispersed carbon nanotube dispersions.
• Chemical dispersion method: Chemical dispersion method mainly involves the dispersion of carbon nanotubes by using various chemical reagents to generate various functional groups on the surface of carbon nanotubes. The common method is to soak the carbon tube in acid for reflux treatment. After acid reflux treatment, most of the oxygen-containing groups with hydroxyl or carboxyl groups are produced on the surface of carbon tubes, which contribute to the spalling of carbon tube bundles, and the existence of modified groups leads to the reduction of van der Waals interaction between carbon tubes, thus broadening the application field of carbon tubes. At the same time, the chemical functional groups (such as carboxylic esters) generated on the surface of the carbon tube can give the carbon tube an electric charge, resulting in the electrostatic repulsion needed to maintain the stable dispersion of the carbon tube.

References

1. HangLe. (2020)  "NiFe nanoparticles embedded N-doped carbon nanotubes as high-efficient electrocatalysts for wearable solid-state Zn-air batteries." Nano Energy. 68: 104293
2. Muqiang Jian.(2017) "Flexible and Highly Sensitive Pressure Sensors Based on Bionic Hierarchical Structures." 27(9):1606066