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Tuesday, May 29, 2012

Spider silk conducts heat better than metals

Science and techno world topic: Physics
Spider silk fascinated materials scientists, because they are very resistant to tearing and yet elastic.Another amazing feature of American engineers have discovered: The threads of golden silk spider conduct heat much better than most of the known materials.

"This is more surprising than spider silk is an organic material," says Wang Xinwei of the Iowa State University. The reason for the high thermal conductivity lies presumably in the structure of the silk protein from crystalline molecule blocks, which are in turn connected via flexible bridges.

Photo: Xinwei Wang Research Group

The higher the thermal conductivity of a material is, the faster heat energy can at a given temperature difference to flow through it. Pure iron as a good conductor of heat and has a value of about 80 watts per meter per degree Celsius temperature difference. Copper bumps this up to five times. The dragline silk of the golden spider on the other hand creates 416 watts per meter per degree, Wang and colleagues report in the journal "Advanced Materials".
If the silk thread drawn out, its thermal conductivity increases again by a fifth and then surpasses even that of silver. Better conductor of heat is only diamond or nanotubes of pure carbon - according to Wang's revolutionizing the new results to date views on the thermal conductivity of organic materials. May thus open up a new path, the thermal behavior of electronic components, or even to improve on clothes, said the researchers.

Research: Xiaopeng Huang, Guoqing Liu, Xinwei Wang, Department of Mechanical Engineering, Iowa State University, Ames
Publication of Advanced Materials, DOI 10.1002/adma.201104668

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