2024 Articles
A structural underpinning of the lower critical solution temperature (LCST) behavior behind temperature-switchable liquids
In this study, we use state-of-the-art X-ray scattering and molecular dynamics to analyze amine-water mixtures that show the unusual lower critical solution temperature (LCST) behavior. The goal is to provide direct experimental evidence for the entropy-lowering molecular cluster formation hypothesized as necessary for LCST behavior. Differential wide-angle X-ray scattering and pair distribution analysis and small-angle X-ray scattering measurements were combined with molecular modeling and liquid-liquid equilibrium measurements, revealing direct experimental evidence for the hypothesis. However, the response of the amine phase to accommodating water is even more subtle than the simple hypothesis suggests, with the formation of robust nanoscale reverse micelles. The techniques developed in this paper can be expected to yield insights in the use of temperature-switchable liquids in solvent extraction and other separations, and the stabilization of organelles in living cells that do not have physical membranes but do require compositional gradients to operate.
Keywords: lower critical solution temperature, switchable solvents, double-differential pair distribution function, complex fluids, molecular cluster structure
Subjects
Files
- 2025_Billinge_Matter_LCST ddPDF MD.pdf application/pdf 523 KB Download File
- 2025_Billinge_Matter_LCST ddPDF MD_SI.pdf application/pdf 1.11 MB Download File
Also Published In
- Title
- Matter
- DOI
- https://doi.org/10.1016/j.matt.2024.09.023
More About This Work
- Academic Units
- Applied Physics and Applied Mathematics
- Earth and Environmental Engineering
- Published Here
- October 21, 2024