What are carbon nanotubes used for, and what are carbon nanotubes

Carbon nanotubes: Guibi**, fine race human hair"Super fiber"

The "super fiber" carbon nanotubes of Guibi ** and Xisai human hair actually belong to the same family as diamond and graphite. As a research hotspot in the field of materials in recent years, carbon nanotubes have been highly valued by scientists from all over the world.

Like centimeters and micrometers, nanometers are a unit of scale, and a nanometer is one billionth of a meter. The carbon nanotubes discovered by humans in 1991 are carbon tubes made of graphite carbon atomic layers, with a diameter of a few nanometers to dozens of nanometers, and the thickness of the tube wall is only a few nanometers, like a hollow cylindrical "cage tube" rolled up by barbed wire. It's so tiny that 50,000 side by side is the width of a human hair, and it's actually a fiber with a very high ratio of length to diameter.

As a new member of the carbon crystal family such as graphite and diamond, carbon nanotubes have high toughness, strong conductivity, excellent field emission performance, both metallic and semiconductor, 100 times higher strength than steel, and the specific gravity is only 1 6 of steel. Because of its peculiar performance, it is called the "super fiber" of the future by scientists.

Although the composition is the same as graphite, the potential uses of carbon nanotubes are very attractive: they can be made into excellent microprobes and wires, reinforcing materials with excellent properties, and ideal hydrogen storage materials. It made wall-mounted TVs even more possible and played a crucial role in nanochips and nanoelectronics, which could replace silicon chips in the future, thus triggering a revolution in the computer industry.

Carbon nanotubes are also an important part of the "nano world". Among nanomaterials, carbon nanomaterials, including carbon nanotubes and carbon nanofibers, have been one of the frontiers of international science in recent years. Judging from the number of carbon nanotubes related to carbon nanotubes published in the core journal of the American "Science Index" recently, China ranks among the top in the world after the United States and Japan.

The development process of carbon nanotubes is as follows: in 1991, Japanese scientists discovered carbon nanotubes; In 1992, researchers discovered that carbon nanotubes exhibit the specific conductivity of semiconductors or good conductors with different curvature structures of the tube wall. In 1995, scientists studied and confirmed its excellent field emission performance; In 1996, Chinese scientists achieved large-scale directional growth of carbon nanotubes; In 1998, researchers used carbon nanotubes as electron tube cathodes; In 1998, scientists used carbon nanotubes to make field-effect transistors that work at room temperature; In 1999, a research team in South Korea made a carbon nanotube cathode color display sample tube; In 2000, Japanese scientists made high-brightness carbon nanotube field emission display sample tubes.

In recent years, Chinese scientists have not only synthesized the longest carbon nanotubes in the world, but also stepped up the application research of carbon nanotubes, developed carbon nanotubes with good hydrogen storage performance and carbon nanotube displays with preliminary display functions, and are using their electron emission properties to develop light-emitting devices.

Guibi **, fine race people"Super fiber"

1.It can be made into a transparent conductive film instead of indium tin oxide as the material for touch screens. 2.

It can be applied to carbon nanotube touch screens. The carbon nanotube touch screen was successfully developed for the first time in 2008. 3.

It can be used as a mold. The inside of carbon nanotubes can be filled with metals, oxides, and other substances, so that carbon nanotubes can be used as molds. 4.

It can be used as an electrode material for electric double-layer capacitors. Electric double-layer capacitors can also be used as energy storage devices. 1.

Carbon nanotubes can be made into transparent conductive films to replace ITO (indium tin oxide) as the material for touch screens. In the existing technology, scientists use powdered carbon nanotubes to prepare solutions that are directly coated on PET or glass substrates, but this technology has not yet entered the mass production stage. 2.

Carbon nanotubes can be applied to carbon nanotube touch screens. The carbon nanotube touch screen was successfully developed for the first time in 2008. Until now, many smartphones have used carbon nanotube touch screens.

3.Carbon nanotubes can be used as molds. The inside of carbon nanotubes can be filled with metals, oxides, and other substances, so that carbon nanotubes can be used as molds.

First, by filling carbon nanotubes with metals and other substances, the thinnest nanoscale wires can be prepared. 4.Carbon nanotubes can be used as electrode materials for electric double-layer capacitors.

Electric double-layer capacitors can be used as both capacitors and energy storage devices. Supercapacitors can be charged and discharged at high currents, with almost no overvoltage, a cycle life of tens of thousands of times, and a wide operating temperature range.

Carbon nanotubes are one-dimensional quantum materials with a special structure.

Carbon nanotubes, also known as bucky tubes, are one-dimensional quantum materials with a special structure (nanometer in radial size, micron in axial size, and basically sealed at both ends of the tube).

Carbon nanotubes are mainly composed of carbon atoms arranged in a hexagonal shape, consisting of several to dozens of layers of coaxial circular tubes. Layers are kept at a fixed distance from each other, approximately, with a diameter of 2 20 nm.

And according to the different orientations of the carbon hexagon along the axis, it can be divided into three types: zigzag, armchair and spiral. Among them, the spiral type carbon nanotubes have chirality, while the zigzag and armchair carbon nanotubes have no chirality.

Structural features:

The carbon atoms in carbon nanotubes are mainly sp2 hybridized, and the hexagonal grid structure has a certain degree of bending, forming a spatial topology, in which a certain sp3 hybrid bond can be formed, that is, the chemical bond formed has a mixed hybrid state of sp2 and sp3.

These p orbitals overlap each other to form highly delocalized bonds outside the graphene sheet of carbon nanotubes, and the bonds on the outer surface of carbon nanotubes are the chemical basis for the recombination of carbon nanotubes and some macromolecules with conjugated properties with non-covalent bonds.

As one-dimensional nanomaterials, carbon nanotubes are lightweight, have perfect hexagonal structural connections, and have many abnormal mechanical, electrical, and chemical properties.

In recent years, with the deepening of the research on carbon nanotubes and nanomaterials, their broad application prospects have been continuously revealed.

Carbon nanotubes, known as bucky tubes, are one-dimensional quantum materials with a special structure.

1. Conductive: carbon nanotubes have a one-dimensional hollow tubular structure, the tube wall is surrounded by a single or multi-layer graphene sheet, the pipe diameter is nanometer, the tube length is micron, and the length-diameter ratio is huge.

2. Super tensile strength: carbon nanotubes have superior mechanical properties, tensile strength of 50-200GPA, equivalent to 100 times that of steel, but the specific gravity is only 1 6 of steel, so it is called super fiber; Hardness comparable to diamond, but more flexible, stretchable, and its maximum elongation is higher than that of any metal; It also has good flexibility, resilience and resistance to distortion.

3. Thermal conductivity: carbon nanotubes have good thermal conductivity, and the axial thermal conductivity is 2000-3000W mk, which is about 10 times that of copper and 3 times that of diamond.

4. Adsorption: carbon nanotubes have a large specific surface area and strong adsorption performance; At the same time, it has good electromagnetic wave absorption and other properties.

Carbon nanotubes can be widely used in conductive pastes for lithium batteries, solar cell coatings, high-strength structural materials, conductive coatings, catalyst carriers, field emission materials, electromagnetic shielding materials and other fields. The Nobel laureate said: "Carbon nanotubes will be the most cheap, environmentally friendly and miracle new material for mankind."

Yes, on the side, there is a long, this is yes, on the side, on the side, a long, this kind of long can deodorize. I can also keep vegetables fresh.

Most of the research and applications of carbon nanotubes have focused on tubes, which range in circumference from a few graphene cells to several hundred, meaning that the diameter of the tube is about.

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Look at the nanotube definitionSee that a nanotube is a hexagonal substance.

Nano Water Pipe Golden Emperor You must read the secretary of the Discipline Inspection Committee.

Carbon nanotubes. It is the most typical one-dimensional nanomaterial, with a great aspect ratio, and its strength and aspect ratio are those of traditional carbon fiber.

1o times more. Theoretically, it is completely feasible for carbon nanotubes to fabricate composites with super-strong chemical properties. At the same time, since the length of carbon nanotubes is in the micron range, there is no effect on the processing properties of the composites, and polymer composites reinforced with carbon nanotubes can be formed into various shapes using traditional plastic processing techniques.

The conductivity of carbon nanotubes was found experimentally.

It can be up to 1000 2000 s cm, and can greatly improve the conductivity of polymer composites with a large current density of 106 A cm2. Due to the large aspect ratio of carbon nanotubes and the network structure formed between them, carbon nanotubes can greatly improve the conductivity of polymers at lower volume ratios without affecting other properties of polymers.

Application in stealth materials.

Carbon nanotubes on infrared and electromagnetic waves.

Stealth: The size of nanoparticles is much smaller than the wavelength of infrared and radar waves, so the transmittance of nanoparticles to this wave is much stronger than that of conventional materials, which greatly reduces the reflectivity of waves; The specific surface area of a nanoparticle material.

3 to 4 orders of magnitude larger than conventional semolina, for infrared light.

and electromagnetic waves also have a much greater absorption rate than conventional materials. Carbon nanotubes have the advantages of high elasticity, low density, good thermal insulation, high strength, superior stealth, good infrared absorption, strong hydrophobicity, etc., and it can be blended with ordinary fibers to make bulletproof and warm stealth military equipment.

Application in energy materials.

Hydrogen storage materials: According to the calculation of 500 kilometers of 5-seater cars, the hydrogen required should be calculated by the normal fuel tank volume, and the hydrogen storage density should be there, and the current hydrogen storage materials can not meet this requirement. Carbon nanotubes are the most potential hydrogen storage materials due to their tube structure and graphite-like layer voids between multi-walled carbon tubes, and foreign scholars have proved that single-walled carbon tubes can adsorb hydrogen by 5%-10% at room temperature and pressure of less than 1 bar.

According to theoretical calculations and recent repeated verifications, it is generally believed that the reversible hydrogen storage and release capacity of carbon nanotubes is about 5%, and even if it is 5%, it is the best hydrogen storage material so far.

Carbon nanotubes can be made into transparent and conductive films to replace ITO (indium tin oxide) as the material for touch screens. In the previous technology, scientists used powdered carbon nanotubes to prepare a solution and directly coated it on PET or glass substrates, but this technology has not yet entered the mass production stage. At present, the successful mass production is the use of ultra-carbon emission nanotube technology; In this technology, the film is extracted directly from an array of super-sequential carbon nanotubes and laid on a substrate to make a transparent conductive film, just like the yarn is extracted from a tampon. At the heart of the technology, the ultra-cis-carbon nanotube array was a new material first discovered by the Tsinghua-Foxconn Nano Center in Beijing in 2002.

The carbon nanotube touch screen was successfully developed for the first time in 2007 and 2008, and was industrialized by Tianjin Funa Yuanchuang Company in 2011. It is different from the existing indium tin oxide (ITO) touch screen in that indium tin oxide contains the rare metal "indium", and the raw materials of the carbon nanotube touch screen are methane, ethylene, acetylene and other hydrocarbon gases, which are not limited by rare mineral resources; Secondly, the carbon nanotube film made by the film laying method has conductive anisotropy, just like a natural built-in pattern, which does not require lithography, etching and washing process, saves a lot of water and electricity, and is more environmentally friendly and energy-saving.

Engineers have also developed a positioning technology that uses the conductive anisotropy of carbon nanotubes to determine the X and Y coordinates of a touch point with only a thin layer of carbon nanotubes. Carbon nanotube touch screens also have the characteristics of flexibility, anti-interference, waterproof, knock and scratch resistance, etc., which can be made into curved touch screens, and have high potential to be applied to wearable devices, smart furniture and other products.

Carbon nanotubes are used as electrode materials for electric bilayer capacitors. Electrical double-layer capacitors can be used both as capacitors and as an energy storage device. Supercapacitors can be charged and discharged at high currents, with almost no overvoltage, a cycle life of up to 10,000 times, and a wide range of operating temperatures.

Electric double-layer capacitors can be widely used in communication equipment such as audio frequency, equipment, tuners, fax machines and fax machines, as well as various household appliances. As an electrode material for electric double-layer capacitors, the material is required to have high crystallinity, good conductivity, large specific surface area, and the micropore size is concentrated in a certain range. At present, porous carbon is generally used as the electrode material, which not only has a wide distribution of micropores (less than 30% of the pores contribute to the stored energy), but also has low crystallinity and poor conductivity, resulting in small capacity.

The lack of suitable electrode materials is an important reason that limits the use of electric double-layer capacitors in a wider range. Carbon nanotubes have large specific surface area, high crystallinity, good conductivity, and the size of micropores can be controlled by synthesis process, so they are an ideal electrode material for electric bilayer capacitors. Due to the open porous structure of carbon nanotubes and the formation of an electric double layer at the interface with the electrolyte, a large number of charges can be accumulated, and the power density can reach 8000 wkg

The measured capacitance capacitance at different frequencies is 102 fg (1 Hz) and 49 fg (100 Hz).Catalyst carrier: carbon nanotube material has a large specific surface area and a large surface atom ratio (about 50% of the total atomic number) The electronic structure and crystal structure of the system are obviously changed, showing special electronic effects and surface effects, such as the diffusion rate of gas through carbon nanotubes is thousands of times that of conventional catalyst particles, and the activity and selectivity of the catalyst can be greatly improved after the catalyst is loaded.

As a new member of the nanomaterial family, carbon nanotubes have great application potential in hydrogenation, dehydrogenation and selective catalysis due to their special structure and surface properties, excellent hydrogen storage capacity and conductivity of metals and semiconductors. Once carbon nanotubes are applied in catalysis, it is expected to greatly improve the activity and selectivity of the reaction, and produce huge economic benefits.