Thermochromic Strip

This thermochromic strip is not particularly special to look at; it appears to be nothing more than a shiny black sheet. But on picking it up, a myriad of colours wash across its surface, giving it a psychedelic pattern of colours. So what is it that causes this abrupt change in appearance by simply being touched?

The strip contains a heat-receptive dye, which changes colour when exposed to different temperatures. The physical contact from one’s hand, therefore, passes energy into the dye, causing the colourful end result; it subsequently reverts to its inky black state when contact is removed and it cools down.

This phenomenon is one that has applications ranging from the commercial to the unorthodox. These strips can be implemented for visually monitoring the temperature of a room or for indicating when a packaged meal is hot enough to be eaten. At the opposite end of its applications range, thermochromic dyes have been applied to t-shirts, allowing them to change colour with body temperature. Perhaps their most unexpected use however comes in the form of a coating that can be applied to urinals – allowing for an entirely new form of artistic expression.