Phase Transitions in Higher-melting Imidazolium-based Ionic Liquids: Experiments and Advanced Data Analysis.

0507799 - ÚCHP 2020 RIV NL eng J - Journal Article
Čanji, Maja - Bendová, Magdalena - Bogdanov, M.G. - Wagner, Zdeněk - Zdolšek, N. - Quirion, F. - Jandová, Věra - Vrbka, P.
Phase Transitions in Higher-melting Imidazolium-based Ionic Liquids: Experiments and Advanced Data Analysis.
Journal of Molecular Liquids. Roč. 292, OCT 15 (2019), č. článku 111222. ISSN 0167-7322. E-ISSN 1873-3166
R&D Projects: GA ČR(CZ) GA17-08218S
Institutional support: RVO:67985858
Keywords : ionic liquids * phase change materials * liquid crystals
OECD category: Physical chemistry
Impact factor: 5.065, year: 2019
Method of publishing: Limited access

As thermal energy storage becomes an increasingly important topic, good knowledge of properties of phase-change materials (PCM) is essential. Among other properties, a good PCM should show a large enthalpy of melting, reproducible melting/solidification cycles, and long-term thermal stability. Temperatures and enthalpies of fusion should be determined at a possibly large range of conditions to allow for a critical evaluation of the experimental data and assessment of the material application potential. In this work, imidazolium-based ionic liquids (ILs) with long alkyl chain substituents 1-hexadecyl-3-methylimidazolium chloride and 1-hexadecyl-3-methyl-imidazolium saccharinate were studied in view of their possible use as phase-change materials. Differential scanning calorimetry (DSC) and the heat-leak modulus (HLM) methods were used to determine the temperatures and the enthalpies of phase transitions in the studied ILs, enabling us to study the influence of the heating and cooling rates on the measured properties. Enthalpies of fusion near to or larger than 100 J·g−1 were found in the studied ionic liquids, making them promising candidates for thermal energy storage. Peaks corresponding to possible liquid crystalline phases in the DSC traces of 1-hexadecyl-3-methylimidazolium saccharinate were observed, pointing to more complex phase behaviour of the studied ionic liquids. Finally, to critically evaluate the experimental data measured in this work, methods based on mathematical gnostics were used. Repeatability of measurements and the degree of mutual agreement between the methods used in this work could thus be determined.


Permanent Link: http://hdl.handle.net/11104/0300801