Scientists from ETH Zurich and the University of Zurich have identified a way to prevent water from forming ice crystals even at extreme sub-zero temperatures. At temps as low as negative 263-degrees Celsius, the water retinas the amorphous characteristics of a liquid. The first step in the process the researcher discovered was to synthesize a new class of lipids to create a soft form of biological matter caleld a lipidic mesophase.
In that material, the lipids spontaneously self-assemble and aggregate to form membranes behaving like natural fat molecules. The membranes adopt an arrangement to form a network of connected channels less than a nanometer in diameter. The special aspect of the structure the lipids form is that there is no room in the narrow channels inside for water to form ice crystals.
Even at extreme sub-zero temperatures the water and lipids don’t freeze. The team used liquid helium to cool a lipidic mesophase that contained a chemically modified monoacylglycerol to minus 263 degrees Celsius, only ten degrees above absolute zero. Even at that very cold temperature, no ice crystals formed.
The scientists say that the key is the ratio of lipids to water. The water content in the mixture has control over the temperature where the geometry of the mesophase changes. One example offered is that if the mixture contains 12% water by volume, the structure of the mesophase will transition in about minus 15-degrees Celsus from a cubic labyrinth to a lamellar structure.
Scientists say that they modeled the new class of lipids on membranes found in certain bacteria. Those membranes help the bacteria to survive in very cold environments. The team says that the new class of soft matter they have devised could be used in applications where water must be prevented from freezing.