Energy is an important industry that plays a huge role in human life. The energy state of the country depends on the work of many scientists in this field. Today they are looking for alternative energy sources. For these purposes, they are ready to use anything, starting with sunlight and water, ending with the energy of air. Equipment that can generate energy from the environment is highly valued.
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 the fullerene.
There are two 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 0ºС, and the second - only at elevated temperatures.
Carbon nanotubes: properties
Mostmodern areas, such as applied chemistry or nanotechnology, are associated with nanotubes, which have a carbon frame structure. What it is? This structure refers to large molecules linked together only by carbon atoms. Carbon nanotubes, whose properties are based on a closed shell, are highly valued. In addition, these formations have a cylindrical shape. Such tubes can be obtained by folding a graphite sheet, or grow from a certain catalyst. Carbon nanotubes, photos of which are presented below, have an unusual structure.
They come in different shapes and sizes: single-layered and multi-layered, straight and sinuous. Despite the fact that nanotubes look quite fragile, they are a strong material. As a result of many studies, it was found that they have properties such as stretching and bending. Under the action of serious mechanical loads, the elements do not tear or break, that is, they can adapt to different voltages.
Toxicity
As a result of multiple studies, it was found that carbon nanotubes can cause the same problems as asbestos fibers, that is, various malignant tumors occur, as well as lung cancer. The degree of negative impact of asbestos depends on the type and thickness of its fibers. Since carbon nanotubes are small in weight and size, they easily enter the human body with air. Further, they enter the pleura and enter the chest, and over timecause various complications. Scientists conducted an experiment and added particles of nanotubes to the food of mice. Products of small diameter practically did not linger in the body, but larger ones dug into the walls of the stomach and caused various diseases.
Getting Methods
Today, there are the following methods for obtaining carbon nanotubes: arc charge, ablation, vapor deposition.
Electric arc discharge. Obtaining (carbon nanotubes are described in this article) in an electric charge plasma that burns using helium. Such a process can be carried out using special technical equipment for the production of fullerenes. But with this method, other modes of arc burning are used. For example, the current density is reduced, and cathodes of enormous thickness 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 it is a mixture of different metal groups. Further, there is a change in pressure and method of spraying. Thus, a cathodic deposit is obtained, where carbon nanotubes are formed. Finished products grow perpendicular to the cathode and are collected in bundles. They are 40 µm long.
Ablation. This method was invented by Richard Smalley. Its essence is to evaporate different graphite surfaces in a reactor operating at high temperatures. Carbon nanotubes are formed as a result of the evaporation of graphite on the bottomparts of the reactor.
They are cooled and collected using a cooling surface. If in the first case, the number of elements was equal to 60%, then with this method the figure increased by 10%. The cost of the laser absolation method is more expensive than all the others. As a rule, single-walled nanotubes are obtained by changing the reaction temperature.
Deposition from the gas phase. The carbon vapor deposition method was invented in the late 50s. But no one even imagined that carbon nanotubes could be obtained with it. So, first you need to prepare the surface with a catalyst. Small particles of different metals, for example, cob alt, nickel and many others, can serve as it. Nanotubes begin to emerge 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, acetylene, ethanol, etc. Ammonia serves as an additional technical gas. This method of obtaining nanotubes is the most common. The process itself takes place in various industrial enterprises, due to which less financial resources are spent for the manufacture of a large number of tubes. Another advantage of this method is that vertical elements can be obtained from any metal particles that serve as a catalyst. Obtaining (carbon nanotubes are described from all sides) became possible thanks to the research of Suomi Iijima, whoobserved under a microscope for their appearance as a result of carbon synthesis.
Main species
Carbon elements are classified by the number of layers. The simplest type is single-walled carbon nanotubes. Each of them has a thickness of about 1 nm, and their length can be much longer. If we consider the structure, then the product looks like wrapping graphite with a hexagonal grid. At its tops 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 covers consisting of fullerene molecules.
The next view is multilayer carbon nanotubes. They consist of several layers of graphite, which are folded into a cylinder shape. A distance of 0.34 nm is maintained between them. A structure of this type is described in two ways. According to the first, multilayer tubes are several single-layer tubes nested in 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: applications
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 its characteristics such as strength, bending, conductivity, it is used in many fields:
- as additives to polymers;
- catalyst for lighting devices, as well as flat panel displays and tubes in telecommunication networks;
- as an electromagnetic wave absorber;
- for energy conversion;
- manufacture of anodes in various types of batteries;
- hydrogen storage;
- manufacturing of sensors and capacitors;
- production of composites and strengthening of their structure and properties.
For many years, carbon nanotubes, whose application is not limited to one particular industry, have been used in scientific research. Such material has a weak position in the market, as there are problems with large-scale production. Another important point is the high cost of carbon nanotubes, which is approximately $120 per gram of such a substance.
They are used as a basic element for the production of many composites, which are used to make many sporting goods. Another industry is the automotive industry. The functionalization of carbon nanotubes in this area is reduced to endowing polymers with conductive properties.
The thermal conductivity of nanotubes is high enough that they can be used as a cooling device for various massive equipment. They are also used to make tips that are attached to the probe tubes.
The most important application area is computer technology. Thanks to nanotubes, especially flat displays are created. They can be used to significantly reducethe overall dimensions of the computer itself, as well as increase its technical performance. The finished equipment will be several times superior to current technologies. Based on these studies, high-voltage kinescopes can be created.
Over time, tubes will be used not only in electronics, but also in medical and energy fields.
Production
Carbon tubing, whose production is distributed between the two types, is unevenly distributed.
So MWNTs make a lot more than SWNTs. The second type is done in case of urgent need. Various companies are constantly producing 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 engaged in the manufacture of MWNT. But other countries, such as Korea and China, are just as good.
Production in Russia
Domestic production of carbon nanotubes lags far behind other countries. In fact, it all depends on the quality of the research in this area. It does not allocate enough financial resources to create scientific and technological centers in the country. Many people do not accept developments in the field of nanotechnology because they do not know how it can be used in industry. Therefore, the transition of the economythe new path is quite difficult.
Therefore, the President of Russia issued a decree, which indicates the development of various areas of nanotechnology, including carbon elements. For these purposes, a special program for the development and production of our own technologies was created.
In order to fulfill all the points of the order, the Rosnanotech company was created. A significant amount was allocated from the state budget for its functioning. It is she who should 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. Also, these funds will be used to purchase high-quality equipment for the production of carbon nanotubes. It is also worth taking care of those devices that will protect human he alth, since this material causes many diseases.
As mentioned earlier, the whole problem is to raise funds. Most investors do not want to invest in research and development, especially for a long time. All businessmen want to see profit, but nanodevelopment can take years. This is what repels representatives of small and medium-sized businesses. In addition, without government investment, it will not be possible to fully launch the production of nanomaterials.
Another problemis the lack of a legal framework, since there is no intermediate link between different stages of business. Therefore, carbon nanotubes, the production of which is not in demand in Russia, require not only financial, but also mental investments. So far, the Russian Federation is far from Asian countries, which are leading in the development of nanotechnology.
Today, developments in this industry are 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 Tambov plant Komsomolets.
Good and bad sides
Among the advantages are the special properties of carbon nanotubes. They are a durable material that does not collapse under the influence of mechanical influences. In addition, they work well for bending and stretching. This is made possible by the closed frame structure. Their application is not limited to one industry. The tubes are used in automotive, electronics, medicine and energy.
A huge disadvantage is the negative impact on human he alth.
Particles of nanotubes, entering the human body, lead to the emergence of malignant tumors and cancer.
The essential side is the financing of this industry. Many people do not want to invest in science, because it takes a long time to make a profit. And without the functioning of research laboratories, the development of nanotechnologyimpossible.
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 the price decreasing, 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.
