Date: 11 months ago   Category: Studies

Chemists from Russia have created the nanotubes contracting when heating - RIA Novosti, 8/23/2018

MOSCOW, 23 Aug – RIA Novosti. Scientists from St. Petersburg have created the first-ever microtubes from the unusual material compressing when heating. "Recipe" on their cultivation has been presented in the Ice magazine Inorganic Chemistry.© Fotolia/Tyler Boyes in carbon nanotubes doesn't thaw at 150 degrees Celsius "we only So far have learned to synthesize microtubes, but haven't studied their thermal behavior. On the basis of fluoride of scandium it is possible to create materials with programmable thermal behavior, but for this purpose it is necessary to study possibilities of receiving composite materials by means of our method" — Larisa Gulina from St. Petersburg State University whose words are cited by the press service of the Russian scientific fund tells. Almost all existing solid materials extend when heating and compress at fall of temperature or increase in pressure. The reason of it is simple – increase in temperatures or pressure decrease forces atoms to fluctuate stronger in a crystal lattice that leads to her expansion and increase in volume of material. For the last hundred years chemists have discovered several substances which behave on the contrary – they extend during the cooling and increase in pressure, and contract during the heating and pressure drop because of features in crystal structure. The striking example of it is the water cooled to a freezing point, ice at ultralow temperatures and also a number of compounds of tungsten, scandium and some other metals. © Photo: Joel Brehm, University of Nebraska-Lincoln Office of Research and Economic Development the Russian physicists have found out why nanotubes carry well out tokucheny as Gulina and her colleagues note, for a long time try to create various microdevices and nanoparticles from similar "abnormal" connections as they can be used for increase in accuracy of various sensors, creation of ideal seals for teeth and a set of other materials with accurately verified thermal properties. The Russian researchers have taken the first step to the solution of this problem, experimenting with scandium fluoride – one of the most perspective and interesting materials behaving in this way in very wide range of temperatures. As scientists have found, microtubes from this substance can spontaneously be formed in mix of salts of scandium and very strong nitric acid if to miss through her couples of ftorvodorod. In that case approximately in an hour on the surface of this solution there will be a white film consisting of a set of nanoparticles of several micrometers. © Boris I. Yakobson et al. More firmly than diamond: scientists investigated properties one-atomic carbon нитиПросветив them by means of a microscope, scientists have found out that part of them represented the hollow microtubes similar in a form to hexagons. Having collected a quantity of these structures, scientists have heated them and have tracked how their sizes have exchanged. These experiences have confirmed that fluoride of scandium has kept the properties, however the St. Petersburg chemists plan to study in more detail how conduct себ



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