Supercooling
Supercooling,[1] also known as undercooling,[2][3] is the process of lowering the temperature of a liquid below its freezing point without it becoming a solid.
Per the established international definition, supercooling means ‘cooling a substance below the normal freezing point without solidification’.
Lacking any such nuclei, the liquid phase can be maintained all the way down to the temperature at which crystal homogeneous nucleation occurs.
Water normally freezes at 273.15 K (0.0 °C; 32 °F), but it can be "supercooled" at standard pressure down to its crystal homogeneous nucleation at almost 224.8 K (−48.3 °C; −55.0 °F).
Constitutional supercooling, which occurs during solidification, is due to compositional solid changes, and results in cooling a liquid below the freezing point ahead of the solid–liquid interface.
Therefore, the minimum thermal gradient necessary to create a stable solid front is given by For more information, see Chapter 3 of[11] In order to survive extreme low temperatures in certain environments, some animals use the phenomenon of supercooling that allow them to remain unfrozen and avoid cell damage and death.
[13] Other animals use colligative antifreezes, which increases the concentration of solutes in their bodily fluids, thus lowering their freezing point.
Fish that rely on supercooling for survival must also live well below the water surface, because if they came into contact with ice nuclei they would freeze immediately.
Animals that undergo supercooling to survive must also remove ice-nucleating agents from their bodies because they act as a starting point for freezing.
[18] Cellular barriers such as lignin, suberin and the cuticle inhibit ice nucleators and force water into the supercooled tissue.
[19] The xylem and primary tissue of plants are very susceptible to cold temperatures because of the large proportion of water in the cell.
Many boreal hardwood species in northern climates have the ability to prevent ice spreading into the shoots allowing the plant to tolerate the cold.
[20] Supercooling has been identified in the evergreen shrubs Rhododendron ferrugineum and Vaccinium vitis-idaea as well as Abies, Picea and Larix species.
This is "pseudo-supercooling" because the phenomenon is the result of freezing point lowering caused by the presence of salt, not supercooling.
This condition is most commonly observed in the oceans around Antarctica where melting of the undersides of ice shelves at high-pressure results in liquid melt-water that can be below the freezing temperature.
[22] This provides a challenge to oceanographic instrumentation as ice crystals will readily form on the equipment, potentially affecting the data quality.
[23] Ultimately the presence of extremely cold seawater will affect the growth of sea ice.
[25] The Coca-Cola Company briefly marketed special vending machines containing Sprite in the UK, and Coke in Singapore, which stored the bottles in a supercooled state so that their content would turn to slush upon opening.
[26] Supercooling was successfully applied to organ preservation at Massachusetts General Hospital/Harvard Medical School.
[31][32] Eftekhari et al. proposed an empirical theory explaining that supercooling of ionic liquid crystals can build ordered channels for diffusion for energy storage applications.
