The days when humanity to dispense fire, stove or steam boiler, are long gone. People need electricity, and more and more. We would like it to be cheap, but its delivery to customers is expensive. Russia’s climate is not conducive to energy: corrosion eats a power pole, in bad weather, snow and ice cover the wires, causing damage to power lines, troubleshooting requires a lot of time, effort and money. On the same problems faced by many northern countries, as well as China and Japan. In recent years, scientists have studied the different countries the opportunity to protect wires and construction of power transmission lines with special coatings. Specialists Institute of Physical Chemistry and Electrochemistry. AN Frumkin Sciences developed and tested a superhydrophobic coating that would prevent ice over the wire, and if it does happen, the ice will be easy to get rid of.
Test superhydrophobic coatings in aqueous aerosol stream at a temperature of -5 ° C and a wind speed of 10 m / s. A minute later, the aluminum sample without coating is a layer of ice appears
Buildup Snow on wires and electric poles — a big problem. Especially dangerous icy rains, when the supercooled liquid droplets fall on a metal surface having a temperature below zero. Let us recall the icy rain, held in December 2010 over central Russia. As a result, only in the Moscow region has been turned off at the same time high-voltage lines 217, 134 high-voltage 220 kV supply center, and more than 10 000 transformer substations.
With the icing lines fighting, of course. Most use mechanical methods, but they require access to power lines, disrupting the normal operation of the site. Besides mechanical treatment does not prevent ice formation, and removes it. You can increase the resistance of the wires passing over them current in a special mode. The wires will heat up and melt the ice, but this method will lead to the loss of energy. In recent years, the deicing began to actively implement solutions that freeze at temperatures much lower than water. These fluids are good in the road sector and aviation, but when transporting energy inefficient. The duration of such "non-freezing liquids" is not long, and regularly apply them to hundreds or even thousands of kilometers of wires unrealistic. All of these methods require direct involvement personnel costs of energy or chemicals, and sometimes unsafe to the environment. Economical to make wires and electric poles of such materials on which water is not delayed, and therefore do not namerznet.
Comparative tests of aluminum wires in a loss of freezing rain (air temperature -4 ° C, humidity 97%)
This is what said in an interview STRF.ru Chief Scientific Officer IPCE RAS Corresponding Member of Russian Academy of Sciences, Doctor of Physical and Mathematical Sciences Lyudmila Boynovich:
"One of the distinguishing features superhydrophobic Materials — self-cleaning surface from dust and other particulate matter at its contact with the liquid droplets. The fact that even at very low slopes superhydrophobic surface water droplets can not slide over it, and roll. The hydrophobic surface properties, for it hardly accumulates water which can crystallize. In addition, the already formed ice, frost or wet snow to such surfaces adhere poorly and are showered with wires under its own weight or wind. "
On an aluminum plate with a superhydrophobic coating (top) does not adhere to the snow. Photographed under snow in the air temperature -3 ° C, 99% humidity and wind velocity 2 m / s
Specialists of the Institute of Physical Chemistry and Electrochemistry. AN Frumkin and SciencesThe Institute for Problems in Mechanics. AY Ishlinsky Sciences showed that aluminum surfaces onto which the superhydrophobic coatings, ice is easily removed. Scientists working with solid and stranded aluminum conductors. First, electrochemical methods were treated wires, causing them to the surface became rough — it appeared micro-and nano-relief. Then applied to the roughened surface hydrophobic agent — ftoroksisilan. On these surfaces in contact with water only pictures protrusions relief, i.e. the real contact area between the liquid and the material decreases several times. A smaller contact area, the smaller the adhesion of ice and water with the surface.
Scientists gave samples obmerznut, and then determining what efforts are needed to pull or twist the wire out of the ice cover. It was found that superhydrophobic surfaces drops of water almost does not melt and easily roll off the surface at angles of inclination less than 15 °. When processing supergidrofobizuyuschey bond strength of ice with aluminum decreases by 2.6 times, unless the ice cover has to twist the stranded cable, and 5-10 times, when the wire is pulled. In this case, traces of ice on the liberated wire remains. From the frequent repetition of this procedure the quality of coverage is practically not affected, it was resistant to mechanical stress. Therefore superhydrophobic coatings can be considered ldofobnym. It is resistant to cyclical swings Temperature from -18 ° C to +25 ° C, typical of central Russia.
"In order to obtain superhydrophobic coating has turned from an art to technology, you need a certain level of development of nanotechnology — says Lyudmila Boynovich. — Nanotolschina layer of hydrophobic agent to achieve maximum mechanical resistance of the contact material and the coating and minimize consumption. The application of a thick layer of hydrophobic agent may cause the coating to peel off due to temperature fluctuations. Furthermore, nanokrivizna surface texture elements efficiently increase its hydrophobicity. "
The researchers note that they have received superhydrophobic coatings can be considered as an effective means of de-icing and snow accumulation on aluminum transmission line elements.
The work was supported by the Presidium of the Russian Academy of Sciences (fundamental research program number 24, "Fundamentals of technology of nanostructures and nanomaterials"), And The Presidential Council on grants and state support of leading scientific schools.
Source of information:
LB Boinovich, AM Emelyanenko, Anti-icing potential of superhydrophobic coatings. Mendeleev Communications, 2013, 23, 3-10;
LB Boynovich and other "ice adhesion strength of contact with a superhydrophobic coating." Reports of the Academy of Sciences, 2013, Volume 448, № 6, p. 675-679.