Balancing a Thermometer on the Equilibrium Position

Lisa A. Kelly, a chemist, associate Nirmala Chandrasekharan have prepared an equilibrium based temperature sensor by encapsulating perylene in a soft and transparent polymer containing styrene and N-allyl-N-methylaniline.

One of the molecules that absorbs the energy, perylene, can do two things with the absorbed light energy. It can emit the light, called fluorescence. This light is blue. The energized perylene can also combine with the aniline molecule built into the polymer to form a high energy molecule pair called an exciplex. This exciplex emits light in the green. The formation of the exciplex is an exothermic reaction.

Upon absorption of the light, an equilibrium mixture of the two forms of perylene is formed that is very sensitive to temperature. The ratio of the intensity of the green light to the blue light can be used with calibration to determine the temperature. There is no doubt that this is an elightened use of the basic concepts of equilibrium and exothermic reactions. It is most likely that the field of polymeric temperature measurement using this complex will become a hot new technology.

Reference:
http://pubs.acs.org/cen/topstory/7939/7939notw4.html
J. Am. Chem. Soc., Sept. 15, 2001.(in press).