A method for producing graphene in a dry ice


28/03/2012

Scientists from the United States and South Korea have developed a cheap way to get a graph of dry ice. Their information, they published in Proceedings of the National Academy of Science.

Graphene, which was discovered by Russian scientists Andrei Geim and Konstantin Novoselov, who received the Nobel Prize, is already recognized as a revolutionary synthetic material of the century. The carbon atoms in the form of perfectly flat conductive sheets are much better than copper have thermal conductivity which exceeds the thermal conductivity of any other material and diamond on the inferior tensile strength.

Scientists do not cease to publish articles that promise to make a revolution with the help of graphs in computers, medicine, and all the electronics, but the problem is the inability to low-cost production of graphene sheets in large quantities.

The new method proposed by scientists, provides for the creation of graphene from graphite and dry ice - carbon dioxide in solid form. Graphite and dry ice in a special mill fray between the balls of stainless steel. According to the scientists, after two days of the mill, graphite turns into "flakes", all the faces are transformed into carboxylic acid groups, which greatly increases their ability to various reactions and allows you to freely dissolve them in such kinds of polar solvents such as water, methanol and dimethyl sulfoxide. Thus, dissolving, "flakes" fall into a plurality of planar thick conglomerates to five monolayers.

For graphene films having larger area, and the solution was precipitated by researchers boards of silicon of 3.5 cm by 5 cm, followed by heating to 900 degrees. During heating the edge of nanolayers gradually lost carboxyl groups and tightly connected with the neighboring "flakes". According to the researchers, this process is limited only by the size of the plate. In a number of tests revealed that the conductive properties of the new material were significantly better than that of its predecessor - the graphene created by the oxidation of graphite.


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