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A gimmick to dye for

发布时间:2019-03-07 07:10:16来源:未知点击:

By Catherine Zandonella THE novelty is wearing off those birthday cards that play a tinny song. So how about a picture that changes when you open the card? A new ink that changes colour when a voltage is applied to it could make that possible, says John Reynolds, a chemist at the University of Florida in Gainsville. The polymer-based ink is cheap enough to be printed onto packaging or interactive business cards, says Reynolds. A tiny watch battery will deliver the power needed to change the shape of the molecules in the dye,