Netsu Sokutei, 49 (1), p. 2, (2022)

特 集 -ソフトマターの物理化学-


Polyamorphism of Polyol Aqueous Solutions

Liquid water behaves differently from other substances at low temperatures. Recent studies of supercooled liquid water suggest the existence of two liquid waters with different densities, low-density liquid (LDL) and high-density liquid (HDL), at low temperatures, the so-called " water polyamorphism", and the fluctuations between the two waters may be responsible for the anomalous behavior of low-temperature water. Here, in order to understand the effect of solute on the polyamorphic behavior of water, I experimentally investigated the polyamorphic transitions of low concentration polyol aqueous solutions under high pressure, which is related to the polyamorphic transition of pure water. From the temperature, solute concentration, and solute nature dependences of polyamorphic transition, it is found that the state of solvent water in polyol aqueous solutions can be consistently classified by two waters, LDL and HDL. In addition, the OH groups in a polyol molecule seem to stabilize HDL-like solvent water, and conversely the hydrophobic groups may stabilize LDL-like solvent water.