Experimental observation of nanophase segregation in aqueous salt solutions around the predicted liquid-liquid transition in water

Lane, Paul D. and Reichenbach, Judith and Farrell, Andrew J. and Ramakers, Lennart A.I. and Adamczyk, Katrin and Hunt, Neil T. and Wynne, Klaas (2020) Experimental observation of nanophase segregation in aqueous salt solutions around the predicted liquid-liquid transition in water. Physical Chemistry Chemical Physics, 22 (17). pp. 9438-9447. ISSN 1463-9084 (https://doi.org/10.1039/c9cp06082k)

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Abstract

The liquid-liquid transition in supercooled liquid water, predicted to occur around 220 K, is controversial due to the difficulty of studying it caused by competition from ice crystallization (the so-called "no man's land"). In aqueous solutions, it has been predicted to give rise to phase separation on a nanometer scale between a solute-rich high-density phase and a water-rich low-density phase. Here we report direct experimental evidence for the formation of a nanosegregated phase in eutectic aqueous solutions of LiCl and LiSCN where the presence of crystalline water can be experimentally excluded. Femtosecond infrared and Raman spectroscopies are used to determine the temperature-dependent structuring of water, the solvation of the SCN- anion, and the size of the phase segregated domains.

ORCID iDs

Lane, Paul D., Reichenbach, Judith, Farrell, Andrew J., Ramakers, Lennart A.I. ORCID logoORCID: https://orcid.org/0000-0002-1844-9936, Adamczyk, Katrin, Hunt, Neil T. ORCID logoORCID: https://orcid.org/0000-0001-7400-5152 and Wynne, Klaas;
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