Need solutions to engineering problems? Look no further than the plants and animals around you. That’s what more and more scientists are doing.
How dry I am: Lotus leaves and gecko toes stay clean and dry because they repel water very effectively. They do this with structures that are billionths of a meter in size. The BBC News reported how an Australian team of chemists has created a super-hydrophobic surface that is “impossible to wet” by imitating the properties of the lotus leaf and gecko foot. A short video clip shows how water just beads off the surface. This technology could lead to better raincoats and self-cleaning fabrics.
Got those butterfly blues: Nature News reported that a Korean team has successfully imitated the microstructure of a Morpho butterfly wing to create the same shimmering blue color that can be seen from many angles when the insect flies. The butterfly uses a combination of regularly-spaced ridges and randomness: “The tight, semi-random packing of the ridges makes the wings appear bright across a wide range of viewing angles.” The Korean team “deposited silica microspheres onto a surface and then sprayed layers of titanium dioxide and silicon dioxide over them, Nature said. “The resulting film… had just the right mix of regularity and disorder to create the even blue colouring.”
The nose knows: An electronic nose is closer to reality, thanks to work by a team from the American Institute of Physics. They placed DNA molecules specially designed to react to certain chemicals on carbon nanotubes that conduct electricity. PhysOrg said, “The researchers are next interested in creating something akin to an actual electronic nose consisting of many individual DNA-based sensors performing the same role as an olfactory receptor.” In biological noses, though, a huge variety of chemicals can be differentiated by a signal chain that expands and compresses the input signals through codes. It appears the electronic version uses a one-to-one type of signalling.
Spider men: The dragline silk of garden spiders continues to baffle materials scientists who would really like to imitate it. Part of the problem is that about 10% of the spider’s silk is ordered, and 90% is disordered. Researchers from Argonne National Lab looked at the disordered portion for clues, PhysOrg reported, “untangling the mysteries of spider silk.” The “amorphous regions are made up of all these proteins that are incredibly complicated,” one researcher said. Another remarked, “When it comes to silks, humans are just so far behind nature in terms of the quality of the materials that we can produce.” ….
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