Energy is an important industry that plays a huge role in human life. The energy condition in the country depends on the work of many scientists in this industry. Today they are looking for alternative sources of energy. For these purposes, they are ready to use anything, starting with sunlight and water, ending with the energy of the air. Equipment that is capable of generating energy from the environment is greatly appreciated.
General information
Carbon nanotubes are extended rolled graphite planes having a cylindrical shape. As a rule, their thickness reaches several tens of nanometers, with a length of several centimeters. At the end of the nanotubes, a spherical head is formed, which is one of the parts of fullerene.
There are such types of carbon nanotubes: metal and semiconductor. Their main difference is the conductivity of the current. The first type can conduct current at a temperature equal to 0º, and the second - only at elevated temperatures.
Carbon Nanotubes: Properties
Most modern areas, such as applied chemistry or nanotechnology, are associated with nanotubes that have a carbon skeleton structure. What it is? By this structure is meant large molecules bonded to each other only by carbon atoms. Carbon nanotubes, whose properties are based on a closed shell, are very much appreciated. In addition, these formations have a cylindrical shape. Such tubes can be obtained by folding graphite sheet, or grow from a specific catalyst. Carbon nanotubes, photos of which are presented below, have an unusual structure.
They come in different shapes and sizes: single-layer and multi-layer, straight and winding. Despite the fact that nanotubes look rather fragile, they are a durable material. As a result of many studies, it was found that they possess such properties as tension and bending. Under the action of serious mechanical loads, the elements do not break and do not break, that is, they can adapt to different voltages.
Toxicity
As a result of numerous studies, it was found that carbon nanotubes can cause the same problems as asbestos fibers, that is, various malignant tumors, as well as lung cancer, arise. The degree of negative influence of asbestos depends on the type and thickness of its fibers. Since carbon nanotubes are light and small in size, they easily enter the human body with air. Further, they enter the pleura and enter the chest, and eventually cause various complications. Scientists conducted an experiment, and added particles of nanotubes to the food of mice. Products of small diameter practically did not stay in the body, but larger ones stuck into the walls of the stomach and caused various diseases.
Production Methods
Today, there are the following methods for producing carbon nanotubes: arc charge, ablation, gas vapor deposition.
Arc discharge. Production (carbon nanotubes are described in this article) in a plasma of an electric charge that burns using helium. Such a process can be performed using special technical equipment for the production of fullerenes. But with this method, other modes of arc burning are used. For example, current density decreases, and cathodes of huge thicknesses are also used. To create an atmosphere of helium, it is necessary to increase the pressure of this chemical element. Carbon nanotubes are obtained by sputtering. To increase their number, it is necessary to introduce a catalyst into the graphite rod. Most often, this is a mixture of different metal groups. Further, there is a change in pressure and spraying method. Thus, a cathode deposit is obtained, where carbon nanotubes are formed. Finished products grow perpendicular to the cathode and are bundled. They have a length of 40 microns.
Ablation This method was invented by Richard Smalley. Its essence is to vaporize various graphite surfaces in a reactor operating at high temperatures. Carbon nanotubes are formed by the evaporation of graphite on the bottom of the reactor.
They are cooled and collected using a cooling surface. If in the first case, the number of elements was 60%, then with this method the figure increased by 10%. The cost of laser absorption is more expensive than everyone else. As a rule, single-walled nanotubes are produced due to a change in the reaction temperature.
Vapor deposition. The method of carbon vapor deposition was invented in the late 50s. But no one even suggested that carbon nanotubes could be produced with it. So, first you need to prepare the surface with the catalyst. As it can serve as small particles of various metals, for example, cobalt, nickel and many others. Nanotubes begin to appear from the catalyst bed. Their thickness directly depends on the size of the catalyzing metal. The surface is heated to high temperatures, and then a gas containing carbon is supplied. Among them are methane, acetone, ethanol, etc. Ammonia serves as an additional technical gas. This method of producing nanotubes is the most common. The process itself takes place at various industrial enterprises, as a result of which less financial means are spent for the manufacture of a large number of tubes. Another advantage of this method is that the vertical elements can be obtained from any metal particles that serve as a catalyst. Obtaining (carbon nanotubes are described from all sides) was made possible thanks to the research of Suomi Iijima, who observed under a microscope their appearance as a result of carbon synthesis.
Main types
Carbon elements are classified by the number of layers. The simplest form is single-walled carbon nanotubes. Each of them has a thickness of about 1 nm, and their length can be much larger. If we consider the structure, the product looks like a graphite wrap using a hexagonal grid. At its vertices are carbon atoms. Thus, the tube has the shape of a cylinder, which has no seams. The upper part of the devices is closed with caps consisting of fullerene molecules.
The next type is multilayer carbon nanotubes. They consist of several layers of graphite, which are folded into the shape of a cylinder. A distance of 0.34 nm is maintained between them. A structure of this type is described using two methods. According to the first, multilayer tubes are several single-layer tubes inserted into each other, which looks like a nesting doll. According to the second, multilayer nanotubes are a sheet of graphite that wraps around itself several times, which looks like a folded newspaper.
Carbon Nanotubes: Application
Elements are an absolute new representative of the class of nanomaterials.
As mentioned earlier, they have a frame structure, which differs in properties from graphite or diamond. That is why they are used much more often than other materials.
Due to such characteristics as strength, bending, conductivity, they are used in many areas:
- as additives to polymers;
- a catalyst for lighting devices, as well as flat displays and tubes in telecommunication networks;
- as an absorber of electromagnetic waves;
- for energy conversion;
- manufacturing anodes in various types of batteries;
- hydrogen storage;
- manufacturing sensors and capacitors;
- production of composites and enhancing their structure and properties.
For many years, carbon nanotubes, the use of which is not limited to one particular industry, are used in scientific research. Such material has weak market positions, as there are problems with large-scale production. Another important point is the high cost of carbon nanotubes, which is about $ 120 per gram of such a substance.
They are used as the main element for the production of many composites, which are used for the manufacture of many sports goods. Another industry is automotive. The functionalization of carbon nanotubes in this area is reduced to providing polymers with conductive properties.
The thermal conductivity of nanotubes is quite high, so they can be used as a cooling device for various massive equipment. Also, tips are made from them, which are attached to the probe tubes.
The most important industry is computer technology. Thanks to nanotubes, extremely flat displays are created. Using them, you can significantly reduce the overall dimensions of the computer itself, as well as increase its technical parameters. Finished equipment will be several times superior to current technology. Based on these studies, high-voltage picture tubes can be created.
Over time, the tubes will be used not only in electronics, but also in the medical and energy fields.
Production
Carbon tubes, the production of which is distributed between their two types, are distributed unevenly.
That is, MWNTs produce much more than SWNTs. The second type is done in case of urgent need. Various firms constantly produce carbon nanotubes. But they are practically not in demand, as their cost is too high.
Production leaders
Today, the leading place in the production of carbon nanotubes is occupied by Asian countries, whose production capabilities are 3 times higher than in other countries of Europe and America. In particular, Japan is manufacturing MWNT. But other countries, such as Korea and China, are not inferior in this indicator.
Production in Russia
Domestic production of carbon nanotubes significantly lags behind other countries. In fact, it all depends on the quality of research in this area. Not enough financial resources are allocated here to create scientific and technological centers in the country. Many people do not perceive developments in the field of nanotechnology because they do not know how this can be used in industry. Therefore, the transition of the economy to a new path is quite difficult.
Therefore, the President of Russia issued a decree indicating the development paths of various areas of nanotechnology, including carbon elements. For these purposes, a special program has been created for the development and production of our own technologies.
In order for all points of the order to be fulfilled, the Rusnanotech company was created. A substantial amount of the state budget was allocated for its functioning. It is she who must control the process of development, production and introduction of carbon nanotubes into the industrial sphere. The allocated amount will be spent on the creation of various research institutes and laboratories, and will also strengthen the existing achievements of domestic scientists. These funds will also be used to purchase high-quality equipment for producing carbon nanotubes. It is also worth taking care of those devices that will protect human health, since this material causes many diseases.
As mentioned earlier, the whole problem is raising funds. Most investors do not want to invest in scientific developments, especially for a long time. All businessmen want to see a profit, but nanotechnology can go on for years. This is what repels small and medium-sized businesses. In addition, without government investment, it will not be possible to fully launch the production of nanomaterials.
Another problem is the lack of a legal framework, as there is no intermediate link between different levels of business. Therefore, carbon nanotubes, whose production in Russia is not in demand, require not only financial, but also mental investments. So far, the Russian Federation is far from Asian countries that are leading in the development of nanotechnology.
Today, developments in this industry are being carried out at the chemical departments of various universities in Moscow, Tambov, St. Petersburg, Novosibirsk and Kazan. The leading manufacturers of carbon nanotubes are the Granat company and the Komsomolets Tambov plant.
Positive and negative sides
Among the advantages, one can single out the special properties of carbon nanotubes. They are a durable material that does not collapse under the action of mechanical stresses. In addition, they work well for bending and stretching. This was made possible thanks to a closed frame structure. Their application is not limited to one industry. The tubes have found application in the automotive industry, electronics, medicine and energy.
A huge drawback is the negative impact on human health.
Particles of nanotubes entering the human body lead to the appearance of malignant tumors and cancer.
A significant aspect is the financing of this industry. Many people do not want to invest in science, as it takes a lot of time to make a profit. And without the functioning of research laboratories, the development of nanotechnology is impossible.
Conclusion
Carbon nanotubes play an important role in innovative technologies. Many experts predict the growth of this industry in the coming years. There will be a significant increase in production capabilities, which will lead to a decrease in the cost of goods. With a decrease in price, the tubes will be in great demand, and will become an indispensable material for many devices and equipment.
So, we found out what these products are.