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Innovative Composite materials based on graphite, produced in Ukraine and almost compete with the other components of the latest developments in this technologic area

2012-03-16
Andrew (Gabriel) Livshits

In the most efficient electrochemical reactors, I have developed programs to create a system of cleaning and regenerating process water without using chemicals, fabrics made from carbon composites, provide almost all the advantages over other alternative technologies

The name of these tissues, is Ethan and Khortytsya and they are the product of innovative companies from the city of Zaporozhye UKRUGLEKOMPOZIT

Given the unusual effect, which becomes an electrochemical reactor with the use of these composite fabrics as electrodes and electrode contact systems, you can make a preliminary conclusion that these materials may at one time were not sufficiently investigated and classified as to their eligibility nano - composite material

These materials have been used for over 10 years and constantly open up more and more interesting features and quality, while in the scientific literature there are more reports of studies on the development of composite materials of carbon and its modifications

Since it was reported that physicists have found a relative of graphen decanter (also two-dimensional allotropic modifications of carbon), unusual electrical properties (the way a fabric Ethan also found unusual electrical properties and unusual version of the conductivity), which can serve as building transistors based on this material. The article appeared in the scientific Physical Review Letters.

In the Countess carbon atoms lie, as in graphen , in the same plane. Unlike the latter, however, there are atoms with double and triple bonds, ie, the resulting structure is different from the regular hexagonal lattice.

As a consequence, there are many different structures carafe - has been studied in the framework of the so-called 6,6,12-bottle, which consists of two types of hexagons with a side of a right and wrong with sides 1 and 3.

Using density functional theory - the basic method for calculating the electronic structure of molecules and condensed matter physics and chemistry based on the laws of quantum mechanics - the researchers concluded that the electrical conductivity of these materials depends on the direction. According to scientists, this property can be used to create transistors.

At present, the decanter (not 6,6,12-bottle) was synthesized only once. According to chemists, who leads Physical Review Focus, in the laboratory is possible to synthesize small fragments of a decanter, but full of sheets, which exhibit unusual properties, yet it was not possible to obtain.

Andre Geim, won the 2010 Nobel Prize for his discovery of graphen, the publication said that "the pitcher - and so it is very interesting stuff, but the new results make it even more interesting." At the same time, he hoped that the creation of practical technologies for the material will take more than 60 years, (referring to the story of the graphen, which was theoretically predicted long before he received in practice).

In early 2009, scientists were able to get graphan. The processing of graphen with hydrogen gas in the presence of an electric current of hydrogen atoms to carbon atoms joined by alternating one on top of "list", the other from the bottom, slightly deforming the planar structure of the source material. The article appeared in the scientific journal Science.
For more information on graphan:

International group of researchers managed to get out of graphen and hydrogen graphan new material. It is stated in a press release on the website of the University of Manchester, whose staff participated in the work.

The article appeared in the scientific journal Science. According to the researchers, the new discovery could be used in the manufacture of electronics, as well as help in the development of hydrogen energy.

The fact that graphen is chemically active (as opposed to material akin to graphite) has been known to scientists for a long time. To get graphan, the researchers placed graphen in hydrogen gas and the gas is passed through an electric current. As a result, the hydrogen molecule disintegrated into atoms, which are joined to the original material.

Recall that a graph is a "list" consisting of a single layer of carbon atoms, which are located at the vertices of a hexagonal two-dimensional (that is, each grid cell is a hexagon) grid. The hydrogen atoms attached to carbon atoms one by one: one from the top "sheet" and the other from the bottom, slightly deforming the planar structure of the source material (see figure).

Theoretically, the existence of graphen was predicted by a group of American scientists in 2006 on the basis of computer modeling. Available on the website arXiv.org preprint of an article that later appeared in the journal Physical Review B.

In contrast to graphen, which is an electrical conductor, a dielectric graphan.
According to researchers, this property of the new material could potentially be used in the manufacture of transistors, subminiature, because it allows to solve one of the main problems of graphen electronics - the complexity of creating conductive paths.

Adding hydrogen atoms to graphen will allow him to get on the regions of graphen. Such regions may be a dielectric, for example, divide a sheet of starting material to the set of conductive strips.

Note that earlier as one of the solutions to the problem of obtaining conductive circuits, the same group of researchers proposed a physically cut into strips of graphen thickness of several nanometers, and glue the contours of them.

In addition, the new material can be used in hydrogen energy. In particular, an international group of researchers found that heating the graphen leads to the release of atomic hydrogen.

Recall that one of the main problems of hydrogen power is the creation of effective ways to store hydrogen. One of the most promising areas of research is to obtain materials that can store the "fuel" in the bound state, in this case in the form of graphen.

Physicists have shown (so far, though, in theory) that the doped graphan can go superconducting at relatively high temperatures. Article scientists have not yet accepted for publication, but its preprint available at arXiv.org.

In the study, researchers conducted a computer simulation of the behavior of doped graphen, ie, graphen, which in some way have been added impurities to change the magnetic and electrical properties of the material.

As a result, scientists were able to determine that such material will go into a state of superconductivity at a temperature of 90 Kelvin (-183 degrees Celsius).
According to physicists, one of the causes superconductivity at such high temperatures is "almost two-dimensional" structure of graphen. This material is obtained from graphen by adding hydrogen atoms are attached to carbon atoms one by one: one from the top "sheet" and the other from the bottom, slightly deforming the planar structure of the source material. In addition, a role played by strong bonds between carbon atoms.

Scientists themselves report that their work is still theoretical. The fact that graphan was first obtained in March 2009, so the practical verification of the results remains a matter of the future. The conditions that exist in grafan in theory, can be observed, according to physicists in doped diamond nano- pin’s. Obtaining the latter, in turn, is a relatively simple affair.

The main obstacle for wider use of superconductors is the necessity of cooling to cryogenic temperatures. If the predictions of physicists will be correct, for the superconductor graphyn enough refrigerator operating at nitrogen.

Researchers from Cambridge have proposed a new method for producing graphen at temperatures as "close to the room." The article appeared in the scientific journal Nature Communications.
At the present time to obtain graphen films is a rather complicated process. At temperatures of about 1000 degrees carbon material is evaporated, after which they condense on specific substrates. After the formation of a film it should have moved directly to the "working" surface.

In the new work, scientists have proposed the following method. In the first stage surface is covered with a thin film of nickel. After that, the film is applied on top of pasta, containing graphite. The resulting "sandwich" was dried. In this part of the carbon atoms penetrate through the natural channels of a nickel film forming underneath a layer one atom, ie graphen. The upper layers are then removed by chemical means.

The new method is easier earlier on several parameters. It does not require expensive and difficult to obtain single-crystal substrates - the film can be formed on various surfaces (in the work of scientists have tested their method on glass, plastic, silicon and other substrates).
In particular, this means that the film can be obtained directly on the working surface, for example, to create electronic circuits. Second, the new method requires drying at temperatures of 25-160 degrees Celsius, which is much easier installation for graphen and its potential value.

Graphen is a two-dimensional layer of carbon atoms which are located at the vertices of a hexagonal grid. This material was discovered coming from Russia, Konstantin Novoselov and Geim Andrew. For their discovery they were awarded the Nobel Prize in 2010. In this paper the researchers used an ordinary graphite and tape, with which they are separated by carbon

A team of researchers from the University of Manchester under the leadership of Leonid Ponomarenko has created an isolated double graphen sheet. The article appeared in the scientific journal Nature Physics, and its preprint available at arXiv.org. A summary of the comments of researchers found in a university news release.

The study investigated a double sheet of graphen - a two-dimensional sheet of carbon just one atom thick, placed on top of another of the same layer. Despite the fact that the spatial layers are close enough, they are isolated from each other (sometimes referred to as a double layer structure, but without the isolation - the terminology is not well established).

The first such double-layer graphen samples were obtained in 2006, ie after only two years after the discovery of the material itself. However, until recently the study of this material was difficult because of the complexity of its receipt.
Now, scientists have managed to create a double sheet of graphen, which is at the top and bottom was covered with a layer of boron nitride. As it turned out, this system has a number of interesting properties.

It was found, for example, that if one of the layers of accumulated a lot of carriers, the second layer is no longer conduct current. "This is the first time that graphen sheet without defects was converted into a detention center" - presented in a press release from the University of Manchester word Ponomarenko.

"If we abstract from the" new "physics, which is set out in our article, the work is of great practical importance. We have shown that graphen is enclosed in a boron nitride is the most promising at the present moment as a basis for creating graphen electronics.

Our construction solves several problems relating to the quality and stability of graphen to create specific instruments, "- said Andre Geim, who participated in the work.
At present, a double graphen extensively studied. In August of 2011 in the journal Science published an article by the same Geim and Konstantin Novoselov, who found that a similar two-dimensional electrons in graphen behave as a liquid crystal. Both scientists received the 2010 Nobel Prize for his discovery of graphen in 2004.

We also know that physicists have proposed a two-dimensional meta-material based on graphen. The new work was published in the journal Science, and its summary is available in a press release the University of Pennsylvania.

The properties of meta-materials depend primarily on the structure and not on the chemical composition. Such materials are capable of "tricky" way to change the path of electromagnetic waves, which leads to unusual optical effects, such as invisibility. If an object is placed near the meta-material, the observer will create the illusion of the absence of the object, as they reflected waves "wallow" in meta-material does not reach the eye of the observer or the detector unit.

Graphen - a allotropic modification of carbon, which is a layer of atoms of that element one atom thick. Graphen has many unique properties, in particular, it is observed a maximum electron mobility among all known materials.
Electrical conductivity of graphen can be easily changed by varying the distance from the grounding plate to the graphen layer. Accordingly, in a single layer of graphen is possible to create a zone of very different conductivity.

Electromagnetic waves propagate in different ways in the layers with different conductivity -, respectively, placing these areas in the "correct" manner, scientists can control the path of propagation of electromagnetic waves.

The work of researchers is still only theoretical. However, in the case of translating ideas into reality physicists meta-materials based on graphen can be claimed in optics and electronics.

Interestingly, Chinese scientists have created a battery based on graphen. Article scientists have not yet accepted for publication in peer-reviewed journal, but its preprint available at arXiv.org
As part of the scientists placed in a solution of copper chloride at room temperature for a pair of electrodes connected by a strip of graphen. Some of these batteries was enough that a voltage of 2 volts, which was enough to light a small LED.
Scientists themselves explain the principle of its battery so - during the thermal motion of ions in the solution hit graphen strip. It knocks out an electron, which turns out to be two options - to go into solution or to the electrode.
Since the mobility of electrons in graphen is much higher than in solution, it chooses the second option. The researchers found that the increase in temperature leads to an increase in performance batteries.
The researchers claim that they were able to eliminate the possibility of occurrence of some unknown chemical reaction on a strip of graphen. How this was done is not reported as supplementary material to this article on arXiv.org not available.

Reading about these and many other studies in this direction, you will notice that such real practical results that are absolutely real as obtained from the use of carbon composite material created by at least 15 years ago, remain unnoticed and not been the subject of deeper research

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