Supercooled liquid shines bright like lava when touched (VIDEO)
The phenomenon, called crystallization-induced emission enhancement, happens when certain luminophores start emitting light more efficiently after turning from a liquid to a solid state. A compound called diketopyrrolopyrrole, or DPP, is among them, and a team of researchers from the University of Michigan used its derivatives to create a solution with unusual properties.
The liquid they created has a melting point of 134 degrees Celsius.
As long as it is kept clean, a liquid can be cooled below its melting point and not turn solid, which is called supercooling. But given a point of nucleation, supercooled liquid quickly crystalizes in a chain reaction. In nature supercooled droplets of water are responsible for freezing rains or the icing of high-flying aircraft.
The DPP8 solution described in the study can remain stable in a supercooled state, going as low as 0 degrees Celsius. Unlike many organic liquids, this one does not crystalize at temperature change, the study said. But even a small amount of shearing force – touch or steering – triggers crystallization. Seeding a living cell on a liquid DDP8 film may trigger the reaction, potentially making the solution a key element for very sensitive medical sensors.
“When cells are seeded on a substrate, they spread and establish focal contacts on the substrate. These focal adhesions transmit intracellular tension generated by the actin cytoskeleton into traction force against extracellular substrate. Simply speaking, cells have ‘hands’ to hold substrate when they attach on a surface and these hands give traction force to hold the surface tight,” Kyeongwoon Chung, a co-author of the study, told RT.
Another possible application is for memory storage. Crystalized DPP8 may be turned back into liquid by simple heating. With dim red standing for 0 and bright gold for 1, the solution could be used in computers using light instead of electricity, researchers say.
“We can write by touching, erase with annealing, and read data with optical image under UV light. But for the practical application, it would require much more development,” Chung said.