Electricity switches a mirror to a window.Thin films of a gadolinium-magnesium alloy possess a curious property: When hydrogen diffuses into the material, the shiny, reflective metal turns as clear as a piece of glass (SN: 3/23/96, p. 182). The alloy is a natural choice for privacy windows, optical shutters, and active displays, but pumping gas Pumping GAS was a two-hour programming block on the Nickelodeon spin-off network, Nick GAS. "Pumping GAS" was commercial-free, with only a thirty-second "pit stop" every now and then. into and out of a chamber isn't a practical switching method. Researchers at Philips Research Laboratories in Eindhoven, the Netherlands, have made a prototype device that changes the alloy from a mirror to a window simply with application of an electric voltage. A thin layer of liquid potassium hydroxide potassium hydroxide, chemical compound with formula KOH. Pure potassium hydroxide forms white, deliquescent crystals. For commercial and laboratory use it is usually in the form of white pellets. covering the alloy sends hydrogen to the metal and takes it back in response to changes in voltage. This design lasts through only 500 switching cycles, though, says Philips' Anna-Maria Janner. A protective layer of palladium peels off the alloy, allowing a hydroxide hydroxide (hīdrŏk`sīd), chemical compound that contains the hydroxyl (−OH) radical. The term refers especially to inorganic compounds. to form. The hydroxide slows the switching time so much that the material no longer turns completely transparent. Janner and her colleagues are now trying to replace the potassium hydroxide with organic materials that won't have this problem. One possibility is a polymer called imidazole imidazole /im·id·az·ole/ (im?id-az´ol) 1. a heterocyclic organic compound in which two of five ring atoms are nitrogen; used as an insecticide. 2. any of a class of antifungal compounds containing this structure. . If the polymer remains stable through many switching cycles, "we will think of making a gel out of it," Janner says. The researchers would then have the basis for a completely solid-state device solid-state device Electronic device that operates on the basis of the electric, magnetic, or optical properties of a solid material, especially one that uses a solid crystal in which an orderly three-dimensional arrangement of atoms, ions, or molecules is repeated . |
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