nano 2008-09-18 20:40
将生物表面涂层复制过来又如何?
[b][size=3]Coating copies microscopic biological surfaces[/size][/b]
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[color=Blue]【纳米科技世界论坛快讯】不知道您有没有想过,未来有一天您的汽车外表像各种生物一样,五颜六色。最近滨州大学的科学家们发现了一种经济实惠的将生物外壳复制的方法。。。。[/color]
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[color=DimGray]Enlarged view of surface of butterfly wings after application of coating using CEFR. Credit: Carlo Pantano/Akhlesh Lakhtakia, Penn State[/color]G~:n d)t
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"Only a small fraction of mutations in evolutionary processes are successful," says Akhlesh Lakhtakia, the Charles Godfrey Binder (Endowed) Professor of Engineering Science and Mechanics. "But, evolution has gone on for at least a billion years. A huge range of biological surface architectures have been created and are available." jp+bA5?G9pNB3F
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Lakhtakia and his colleagues, Carlo G. Pantano, distinguished professor of materials science and engineering, and director of Penn State's Materials Research Institute, and Raúl J. Martín-Palma, visiting professor, Penn State, and professor department of applied physics, Universidad Autónomia de Madrid, used the conformal evaporated film by rotation (CEFR) technique, to produce coatings that capture the micro and nano structure of biological surfaces in a thin coating of glass. The results appear in recent issues of Applied Physics Letters and Nanotechnology.*G-lv.W
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In the CEFR technique, the researchers thermally evaporate the material that forms the coating in a vacuum chamber. The object receiving the coating is fixed to a holder and rotated about once every two seconds. The researchers have coated butterfly wings and a fly, creating replicas of these templates with identical surface characteristics. The researchers are using chalcogenide glasses composed of varying combinations of germanium, antimony and selenium.
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"With the right temperature, which is room temperature, and the right pressure and rotation speed, the coating process takes about 10 minutes and deposits a 500- nanometer layer," says Lakhtakia.}^s.P ~V,J9~
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Some biostructures, such as moth's eyes, which are duplicated to produce moth's-eye lenses, can be mechanically created by engineers, but it is painstaking and expensive work. These lenses, that capture nearly all available light, have applications in optoelectronic and photovoltaic applications. Other biostructures do not lend themselves to synthetic reproduction.u#];q"@X
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"In that case, perhaps we need to replicate the actual structure," says Lakhtakia. "One insect has an iridescent shell that does not change colors as many shiny ones do. No one has made this type of material artificially because we do not know the mechanism by which it retains its color, but making a template from the actual insect would replicate the fine structure of the surface."
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Many things in the natural world are colored not by pigment, but by surface structure. The way light interacts with the surface creates the color, rather than any tint or chemical. Reproducing the surface reproduces the color. Surface properties include not just visible light characteristics, but also infra red, thermal, stickiness and other characteristics.