Exploring the interplay of structural dynamics and thermodynamics in supercooled aqueous solutions
by
B5:1036
AlbaNova Main Building
This half-time seminar summarizes research on the structural, thermodynamic, and dynamic properties of supercooled aqueous solutions, with a focus on elucidating the role of nanometer-scale structural heterogeneities in water's anomalous behavior. The study focuses on dilute and intermediate concentrations of glycerol-water solutions, which serve as model systems that enable access to water's metastable “no-man’s land" while avoiding crystallization. Glycerol is a commonly used cryoprotectant that inhibits crystallization by integrating into the hydrogen-bond network of water. Evaporatively cooled microdroplets of a dilute water-glycerol solution, reveal that this small structural frustration of the network, has widespread effects on the nanoscale density fluctutations of water. In addition, when investigating higher glycerol concentrations, a first-order-like transition is observed, prior to crystallization, accompanied by a pronounced dynamical slowing down. This transition is hypothesized to be of spinodal-type character. A wide combination of experimental and computational methods is employed, including small- and wide-angle X-ray scattering and X-ray photon correlation spectroscopy at synchrotron and X-ray free-electron laser facilities, complemented by molecular dynamics simulations and phase-field modeling. Overall, these findings clarify the coupling between structural dynamics and thermodynamics in supercooled aqueous systems.