Discovery of water that looks like spiral liquid crystals at the interface of high-pressure spiral ice and water – The mysterious relationship between water and mirrors – | University of Tokyo

January 11, 2024
Tohoku University
Hokkaido University
University of Tokyo
Tottori University

Key points of presentation

• We have discovered the eccentric system in uncharted water that appears at the high-pressure water-ice interface III (note 2), which contains chirality (note 1).
• We have succeeded in capturing dynamics that suggest the possibility that the unknown water takes on a liquid crystalline state (observation 3) with chirality.
• We called the unknown water by the English name “homogeneous water” and the Japanese name “alotropic immiscible water” (Note 4).
• This finding provides a new perspective on the relationship between decentralization and water in life.

Presentation summary

Water is familiar and extremely important to living organisms, including humans, and is also a liquid with strange properties that control many natural phenomena. In addition, chirality, the property of mirror structures being different from each other, such as the relationship between right and left hands, exists universally in nature and is an important property related to the origin of life.

Associate Professor Hiromasa Shinki of the Institute of Multidimensional Materials Science, Tohoku University, Professor Yuki Kimura of the Institute of Low-Temperature Science, Hokkaido University, Professor Hiroki Nada of the Department of Mechanical Physics, College of Engineering, Tottori University, and Advanced Science Research Department, Graduate School of Arts and Science, University of Tokyo. The research group, led by Associate Professor Tetsuya Hama from the institute, has conducted research so far that has discovered unidentified low- and high-density waters that do not mix with water. Natural water that forms at the different interfaces of glacial water, in addition to water similar to liquid crystals. This time we discovered that there is chirality in the wave pattern that occurs when unknown liquid-crystal-like water appears at the interface between water and high-pressure ice III, which has chirality in its crystal structure. This showed for the first time in the world that the unknown water appearing at the interface between Ice III and water may be a liquid crystal with chirality. This result will contribute to a wide range of scientific fields related to water and decentralization, regardless of field.

This result was published online in Physical Chemistry Letters, a physical chemistry journal, on January 10 at 6:00 PM (PST).

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Glossary of terms

Note 1. No conditionality
It refers to two structures in the mirror matching relationship that have different properties. The presence of eccentricity is called a spiral, and a typical example of a spiral structure is the shape of the human hand. When you reflect the shape of your right hand in the mirror, it becomes the shape of your left hand, and because these mirror images are different in shape, the hand shape has chirality. On the other hand, for example, the structure of a cube reflected in a mirror is a cube, and mirror images of the cube show the same structure, so the cube has no chirality. The absence of decentralization is called achiral. In addition to the shape of the human hand, an example of an eccentric structure is the helical structure containing helices for the right and left hands.

Observation 2. High-pressure ice III
The ice we usually see is I ice_HIt is classified into hexagonal crystal structure, which has a core structure of hexagonal columnar water molecules. On the other hand, there is also high-pressure ice, which crystallizes under water pressure. High-pressure ice is I ice_HIt has a different crystal structure. There is also high-pressure ice that crystallizes at temperatures above 0°C. Ice III, which we focused on in this research, is a type of high-pressure ice that is classified as having a crystalline structure called the quadrilateral system, and it has a basic lattice in the form of a rectangular parallelepiped with a square base. Furthermore, because the water molecules that make up Ice III are helically arranged, the crystal structure of Ice III is characterized by asymmetry.

Note 3. Liquid crystal
A state of matter that lies between a crystal and a liquid and, unlike glass, is loosely organized. In other words, it is a state of matter that combines the periodicity and anisotropy of crystals with the fluidity of fluids.

Note 4. Water is immiscible.
Its name, in this study, is a general term for unknown water that separates from bulk water at the water-ice interface (high-pressure ice). The name is based on the scientific terms “allotrope” and “immiscible liquid.” Allotropy is a term used to refer to a group of materials, such as graphite and diamond, that are composed of the same atoms but exhibit different properties due to a different arrangement of the atoms. On the other hand, liquid immiscibility is a term that refers to the phenomenon in which liquids, such as water and oil, do not mix with each other. Immiscibility is usually observed between liquids composed of different elements, but since water and unknown water are the same water, they can be considered an immiscible liquid of allotropes. Therefore, the unknown water is called allotropic immiscible water.