What happens when water cooled @ -263 C?
Sreelakshmi P Vijayan
Scientists cool water to -263° C without freezing it. Can you believe it? Yes, researchers have explored an idea to keep water in liquid state at temperatures approaching absolute zero. Conventionally, we all know that water freezes at zero degree Celsius (32 oF).
A team of scholars in Switzerland discovered a way to reduce the temperature of water to a minimum of -263° C (-441.4 oF) without freezing it. This unlocks up a wide range of possibilities towards the structural molecular study of compounds at extreme temperatures. At zero degrees, water turns to ice and water molecules on the surface commence to crystallize to form ice. A seed crystal is formed, around which a crystal structure can form to create a solid. That is, nearby molecules spreads around it and continues on until the whole body of water is frozen solid. In this arrangement, the water molecules have an organized 3D lattice than the normal disordered state of water molecules. This characteristic allows water to flow freely.
Scholars of ETH Zurich and the University of Zurich, termed this property of water at -263° C as lipidic mesophase, where the water molecules behave as much as natural fat/lipid molecules and they gather themselves or self-assemble to form membranes. These membranes form microscopic channels of nano scale which prevents the possibility of formation of ice crystals in them. Hence water remains in its disordered form of flowing nature when cooled to extreme temperature. Confinement prevents low-temperature crystallization of water molecules into a hexagonal structure and build an amorphous state of water. The scientists designed a group of synthetic lipids specially designed with cyclopropyl modifications in their hydrophobic chains which enables the preservation of water to amorphous state under ~10 K due to Nano confinement.
During conventional freezing, when ice crystals form, it damages and break membranes and large bio-molecules which avoids their further structural and functional analysis. To a solution to this dilemma, the scientists in Massachusetts General Hospital introduced a new super cooling technique where water surface is sealed with a hydrocarbon-based oil which prevented the water meeting air to form the first ice crystals. This helped them to store a sample of liquid water at -20° C (-4° F).
Their main focus was to give investigators a novel idea to enable the study of molecular structures at very low temperature range devoid of ice-interfering crystals. It also aids to understand how water and lipids interrelate under such extreme conditions of temperature and geometrical confinement.
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Check your knowledge
Nano confinement effect arises when the dimension of a pore is reduced to nanoscale, and brings a new emerging physical phenomenon causing a shift in curvature-dependent effect and critical properties. This causes variation in surface tension in Nano pores.
Water freezes at zero degree Celsius. Anomalous expansion of water occurs at 4oC. That is at 4oC, instead of contracting water expands.
In ice permanent hydrogen bonds are present which results an interconnected hexagonal framework of water molecules which cages like space remain in their bonding. This makes ice less dense than air.