Guest_Jim_* Posted May 15, 2015 Posted May 15, 2015 Typically when a material's temperature crosses a transition point, it will change phase, but there are ways around this, allowing a phase to persist when you would not expect it. Researchers at the University of Michigan have demonstrated this quite elegantly when they balanced two opposing crystallization mechanisms in a material. This resulted in the material staying liquid about 200 ºF below its freezing point. The material the researchers were working with is part of a family of organic materials commonly used as pigments in electronics. They all feature a rigid core with two flexible side chains, and depending on the length of the chains, the molecules will take on one crystal structure or another. What the researchers did is balance the chains' length to cause the two modes to counter each other. Normally the material crystalizes at 273 ºF but this balance allowed it to stay liquid at 41 ºF, and cooling it further caused it to solidify into a gas. While in its supercooled state, the material was sensitive to pressure, depending on its temperature. At high temperatures even the weight of a cell would cause it to crystallize, but at room temperature and lower, a stylus was required. Even then, the crystallization was so sluggish that the researchers could write messages in the material, as the crystallized regions glowed under UV light. This material could have some interesting uses, including as a biosensor and as an optical memory. Its ability to encode information optically could be useful, but much more work is required to develop its potential. Source: University of Michigan Back to original news post Share this post Link to post Share on other sites More sharing options...
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