my recent articles |
| Crystals twist about in response to light |
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11 April 2007, for New Scientist All it takes is a burst of light to make a new class of shape-changing crystals snap into different configurations. To demonstrate the trick, Japanese researchers created a tiny rod made from the crystal that flings a far-heavier gold sphere when stimulated with light. They say the material could find practical applications as tiny light-triggered switches, valves, and pumps. Crystals that change shape in response to electricity are known as piezoelectrics, and are already widely used. But researchers have been searching for useful materials that change shape in response to light for some time. There are many examples, but they generally move slowly, show only small changes in shape or size, or are unstable. Now Masahiro Irie of Kyushu University in Japan and colleagues have found a type of crystal that could be much more useful. They created the crystal out of molecules called diarylethenes, and found that they expand or twist when hit with the right shade of ultraviolet light. Read the rest on the New Scientist site. |