Thermochromic Liquid Crystals (TLC's) are highly sensitive materials that respond to temperature. Liquid crystals change from black to a rainbow of colors and then back to black again upon heating. Upon cooling the reverse color change occurs. They became popular with the well-known mood ring and are now available in a wide variety of useful and exciting products.
Liquid crystals can be formulated into thermometers with a wide or narrow temperature sensitivity, and can be made into any size or shape. Temperature monitoring from low freezer temperatures, to high hot water temperatures can be supplied showing a single trigger temperature or a multi-event thermometer. Examples of liquid crystal thermometers are aquarium thermometers, forehead thermometers, refrigerator thermometers, and urine specimen thermometers. Custom applications are also available.
Some other examples of liquid crystal applications are shown
below:
There are some limitations to using liquid crystals. Unfortunately, liquid crystals are very difficult to work with and require highly specialized printing and handling techniques. Liquid crystals are also more expensive than other thermochromic inks. They are adversely effected by high temperatures, ultra violet light, and strong solvents or chemicals.