Pressure-induced liquid-liquid transition in a family of ionic materials.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35292645.
- Also identified by DOI 10.1038/s41467-022-29021-0 and PMC identifier 8924164.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Liquid-liquid transition (LLT) between two disordered phases of single-component material remains one of the most intriguing physical phenomena. Here, we report a first-order LLT in a series of ionic liquids containing trihexyl(tetradecyl)phosphonium cation [P<sub>666,14</sub>]<sup>+</sup> and anions of different sizes and shapes, providing an insight into the structure-property relationships governing LLT. In addition to calorimetric proof of LLT, we report that ion dynamics exhibit anomalous behavior during the LLT, i.e., the conductivity relaxation times (τ<sub>σ</sub>) are dramatically elongated, and their distribution becomes broader. This peculiar behavior is induced by isobaric cooling and isothermal compression, with the τ<sub>σ</sub>(T<sub>LL</sub>,P<sub>LL</sub>) constant for a given system. The latter observation proves that LLT, in analogy to liquid-glass transition, has an isochronal character. Finally, the magnitude of discontinuity in a specific volume at LLT was estimated using the Clausius-Clapeyron equation.