Color Changing Paint
Various technologies exist for making paints that change color. Thermochromic paints and coatings contain materials that change conformation when heat is applied, and so they change color. Liquid crystals have been used in such paints, such as in the thermometer strips and tapes used in aquaria. Photochromic paints and coatings contain dyes that change conformation when the film is exposed to UV light, and so they change color. These materials are used to make eyeglasses.
Color changing paints can also be made by adding halochrome compounds or other organic pigments. One patent cites use of these indicators for wall coating applications for light colored paints. When the paint is wet it is pink in color but upon drying it regains its original white color. As cited in patent, this property of the paint enabled two or multiple coats to be applied on a wall properly and evenly. The previous coat/s having dried would be white whereas the new wet coat would be distinctly pink. Ashland Inc. introduced foundry refractory coatings with similar principle in 2005 for use in foundries.
Electrochromic paints change color in response to an applied electric current. Car manufacturer Nissan has been reportedly working on an electrochromic paint, based on particles of paramagnetic iron oxide. When subjected to an electromagnetic field the paramagnetic particles change spacing, modifying their color and reflective properties. The electromagnetic field would be formed using the conductive metal of the car body. Electrochromic paints can be applied to plastic substrates as well, using a different coating chemistry. The technology involves using special dyes that change conformation when an electric current is applied across the film itself. Recently, this new technology has been used to achieve glare protection at the touch of a button in passenger airplane windows.
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Famous quotes containing the words color, changing and/or paint:
“Since the quarrel
Will bear no color for the thing he is,
Fashion it thus: that what he is, augmented,
Would run to these and these extremities.”
—William Shakespeare (1564–1616)
“The queers of the sixties, like those since, have connived with their repression under a veneer of respectability. Good mannered city queens in suits and pinstripes, so busy establishing themselves, were useless at changing anything.”
—Derek Jarman (b. 1942)
“When young people are too rigidly sequestered from [the world], their lively and romantic imaginations paint it to them as a paradise of which they have been beguiled; but when they are shown it properly, and in due time, they see it such as it really is, equally shared by pain and pleasure, hope and disappointment.”
—Frances Burney (1752–1840)