Thermochromic inks are more expensive than regular inks, but they still find their way into innovative products, from clothes and cars to papers, paints and bathroom fixtures. Beer and energy drink companies are known for incorporating flashy, temperature-sensitive graphics into their products. Leuco dyes don't interfere with recycling, so they're environmentally sound, too.
A company called Moving Color makes color-changing tiles for home decorating. Install the tiles in your shower and watch as the black tile shifts to various bright hues. Or position them near lights and they'll change in response to heat from the bulbs.
Various manufacturers integrate leuco dyes into shirts, skirts and other clothing. Press your hand to these materials and that imprint will linger, offering a weirdly eye-catching appeal.
Some baby bottles employ these inks to indicate when they're hot. Plastic coffee cup lids can do the same. Both are visually appealing, but they serve a practical purpose as well. One company even makes a toilet seat that changes color when body heat is applied, so you'll know if someone has used that particular toilet very recently.
Added to wallpaper or wall paint, these inks hold all sorts of interior decorating potential. At the right temperature, for instance, those vines on your wallpaper would actually bloom into gorgeous pink flowers. If you have the dough, you can ante up for a color-changing paint job for your car, too.
The artistic and aesthetic appeal of these dynamic inks is endless. As chemists continue improving these inks, you can expect to see more and more products that incorporate them. And then you'll be able to upgrade many of the products you own to reflect just about any color of the rainbow.