Original title: Liquid-liquid phase separation precedes crystallization in supercooled water-glycerol solutions
Iason Andronis, Sharon Berkowicz, Mariia Filianina, Maddalena Bin +9 · September 2026
Freezing biological samples requires keeping them safe from ice damage. Scientists study supercooled water-glycerol solutions to see what happens before freezing, but separating liquid changes from ice formation is difficult. Researchers tracked a deeply supercooled water-glycerol solution cooled to cryogenic temperatures of 172 K using advanced X-ray scattering techniques. They watched both molecular changes and motion over time. They discovered that the liquid undergoes sudden molecular changes and splits into microscopic patches before any ice forms. During this transformation, movement slows down and shows ballistic-like, hyper-diffusive relaxation. Ice crystals only form later. Computer simulations match these findings through a process called spinodal decomposition, confirming that the liquid separates into distinct liquid states before ice crystals appear.
Imagine a pot of oil and vinegar salad dressing that you chill in the fridge. Normally they stay mixed if you shake them, but as they get very cold, they suddenly split into separate blobs of oil and vinegar before anything freezes solid. In this paper, water and glycerol behave like that dressing—they separate into two distinct liquid regions at low temperatures, and only later do ice crystals appear.
Cryopreservation—freezing biological samples like cells or tissues—relies on avoiding ice damage. If water-glycerol mixtures first split into two distinct liquid phases before freezing, that changes how we design cooling protocols. Understanding this hidden step could lead to better preservation of organs, vaccines, and embryos.
The abstract does not specify the exact composition of the water-glycerol solution or the cooling rate used. It also does not confirm that liquid-liquid phase separation occurs in other aqueous systems or under conditions relevant to practical cryopreservation. The phase-field simulations are qualitative, not quantitative predictions.
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Liquid-liquid phase separation precedes crystallization in supercooled water-glycerol solutions — Iason Andronis, Sharon Berkowicz, Mariia Filianina et al.
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.