Add to favorite
Subscribe to our Newsletters Subscribe to our Newsletters Get Daily Updates RSS

Clean as Lotus
December 1, 2009 19:16

Lotus leaf and petals

Recently researchers from all over the world started paying attention to the surfaces, which like lotus, show the ability to self-purification. Buddhists know about this lotus property for hundreds of years, since this flower symbolizes divine purity and innocence for followers of this religion.

Well, superhuman powers have nothing to do with this property of lotus the thing is that lotus leaves have special structure. They are all covered with fanciful coarse papulas of various sizes from micro- to nano-papulas. These papulas are in their turn covered with tiny filaments. If we place a drop of water on lotus leaf, it wont be able to go between the papulas, because their surface is hydrophobic (water-repellent), and would lie on leafs surface like a fakir lies on nails. However, more often a drop easily slips off leafs surface, without wetting it, and takes all dirt with it.

Researchers from various countries of the world developed different approaches, which allow them to imitate coarse surface of the unusual flowers leaves. There are several methods to create required surface pattern, and one of them is modern technique of nanolithography. But there is a problem: many materials, which can be structured by means of nanolithography, have hydrophilic (water-loving) surfaces, thus they cannot be directly used for lotus-effect. Moreover, in his case the combination of micro- and nano-relief will only increase wetting ability and drop adhesion.

How can we change properties of such a heterogeneous surface in order to make it fully hydrophobic? Many traditional techniques appear to be non-applicable due to complex interaction of bearing surface relief and wetting processes.

Carbon dioxide pressure-temperature phase diagram
Russian scientists from the physics faculty of Moscow State University and Nesmeyanov Institute of Organoelemental Compounds applied a combination of two techniques and suggested an elegant solution to the burning problem of modern science. The scientists used the hydrofobization technique by means of supercritical carbon dioxide a compound, which is stable under high temperatures and pressures. Under extreme conditions the carbon dioxide looks like liquid, but it is not. For supercritical carbon dioxide theres not such a problem and wetting. This substance gets between papulas of a surface, treated with nanolithography, as deep as it is required, dissolving many other substances and delivering them uniformly to all surface irregularities. In normal conditions carbon dioxide is a gas, and it escapes, when hydrofobization process is over, leaving the surface modified.

As a hydrofobization agent researchers used ultrafine Teflon (polytetrafluoroethylene), which is perfectly dissolved by supercritical carbon dioxide. Researchers showed than the combination of two techniques provides a long-term stability of super-hydrophobic properties of new surfaces, w which strongly resemble lotus leaf.

Can we use these materials in our everyday life? Why not? May be we cannot get self-purifying clothes, but we can make materials for household appliances, which need clean surfaces.

Source: Science News

Kizilova Anna


Next Previous

You might also find interesting:

Scientists From Yakutia Discovered a New Civilization Meet Waybot Smart Robot Created in Russia Special Gel to Improve Oil Production Electronic Nose for Healthy Lifestyle Hen Eggs Can Carry Human Proteins

Comment on our site

RSS   twitter   facebook   submit

Bookmark and Share

search on the map
Yuri Gagarin  Russian hockey  Andronaut  Icon Painting  David Cameron  Charity  Dagestan  children  Traditions and Customs of Karelia  Nizhny Novgorod  Festivals in Moscow  Kaliningrad Region  Mercedes-Benz Fashion Week Russia  Music Festival Crescendo  Moscow  Exhibitions in Moscow  Sokolniki  Chegemskie Waterfalls  Mikhail Larionov  Sergey Guriev  Russian tourists  Illarion Golitsyn  Novosibirsk  Boris Eifman   Russian fashion designer  Russian Cinema  Filipp Malyavin  Moscow Museums  Domodedovo  Vladimir  Feodosiya  Mosque  Alexander Tikhomirov  Anatoly Zverev  Russian International  Fashion and Style in Photography  Krasnodar region  human rights  Russian business  Roscomnadzor  Proton  Russian regions  Russian tourism  Russian politicians  travel to Russia  Moscow hotels  UAE visa  Film Restoration  Russian Astronauts  St. Petersburg 

Travel Blogs
Top Traveling Sites