Advanced search
Start date
Betweenand

A Raman Spectroscopy study of the glass transition of ionic liquids under high pressure

Grant number: 14/15049-8
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): November 01, 2014
Effective date (End): October 31, 2018
Field of knowledge:Physical Sciences and Mathematics - Chemistry
Principal Investigator:Mauro Carlos Costa Ribeiro
Grantee:Thamires Andrade Lima
Home Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Associated research grant:12/13119-3 - Vibrational spectroscopy in condensed phases, AP.TEM
Associated scholarship(s):16/24241-5 - Studying the dynamics of glass forming ionic liquids by neutron and X-ray scattering, BE.EP.PD

Abstract

Several room temperature molten salts, the so-called ionic liquids, are viscous liquids, which are easily supercooled with typical glass transition temperature Tg = 190 K. In the Molecular Spectroscopy Laboratory of IQ-USP, LEM/IQ-USP, we have been studying several issues on the dynamics of glass transition of ionic liquids by Raman spectroscopy as a function of temperature. In this work, we will study the glass transition at room temperature of ionic liquids under high pressure by using a diamond anvil cell (DAC) allowing for ca. 5.0 GPa of applied pressure. The relevance of pressure in studying glass-forming liquids relies on the fact that pressure addresses the role played by density, and therefore free volume, from thermal energy effects. The spectral window of interest is the low-frequency range, w < 100 cm-1, as it directly probes the intermolecular dynamics. Raman spectra within the low-frequency range result from fast (picoseconds) relaxation processes and intermolecular vibrational dynamics, the so-called boson peak. The relative contribution of relaxation and vibration exhibits remarkable temperature dependence, and in this work we intend the study of the pressure dependence. The aim of this work is to compare temperature and pressure effects, as it has been proposed that relaxation in different thermodynamic states before or after the glass transition might be determined by free volume or thermal energy.

Scientific publications (7)
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
LIMA, THAMIRES A.; FARIA, LUIZ F. O.; PASCHOAL, VITOR H.; RIBEIRO, MAURO C. C. Exploring the phase diagram of the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesufonyl)imide. Journal of Molecular Structure, v. 1183, p. 149-156, MAY 5 2019. Web of Science Citations: 1.
LIMA, THAMIRES A.; RIBEIRO, MAURO C. C. Low-frequency Raman spectra of a glass-forming ionic liquid at low temperature and high pressure. Journal of Chemical Physics, v. 150, n. 16 APR 28 2019. Web of Science Citations: 0.
LIMA, THAMIRES A.; FARIA, LUIZ F. O.; PASCHOAL, VITOR H.; RIBEIRO, MAURO C. C. Communication: Glass transition and melting lines of an ionic liquid. Journal of Chemical Physics, v. 148, n. 17 MAY 7 2018. Web of Science Citations: 5.
FARIA, LUIZ F. O.; LIMA, THAMIRES A.; FERREIRA, FABIO F.; RIBEIRO, MAURO C. C. Ultraslow Phase Transitions in an Anion-Anion Hydrogen-Bonded Ionic Liquid. Journal of Physical Chemistry B, v. 122, n. 6, p. 1972-1980, FEB 15 2018. Web of Science Citations: 3.
FARIA, LUIZ F. O.; PASCHOAL, VITOR H.; LIMA, THAMIRES A.; FERREIRA, FABIO F.; FREITAS, RAFAEL S.; RIBEIRO, MAURO C. C. Local Order Disorder Transition Driving by Structural Heterogeneity in a Benzyl Functionalized Ionic Liquid. Journal of Physical Chemistry B, v. 121, n. 42, p. 9902-9909, OCT 26 2017. Web of Science Citations: 2.
FARIA, LUIZ F. O.; LIMA, THAMIRES A.; RIBEIRO, MAURO C. C. Phase Transitions of the Ionic Liquid [C(2)C(1)im][NTf2] under High Pressure: A Synchrotron X-ray Diffraction and Raman Microscopy Study. Crystal Growth & Design, v. 17, n. 10, p. 5384-5392, OCT 2017. Web of Science Citations: 8.
LIMA, THAMIRES A.; PASCHOAL, VITOR H.; FARIA, LUIZ F. O.; RIBEIRO, MAURO C. C. Unraveling the Stepwise Melting of an Ionic Liquid. Journal of Physical Chemistry B, v. 121, n. 17, p. 4650-4655, MAY 4 2017. Web of Science Citations: 4.

Please report errors in scientific publications list by writing to: cdi@fapesp.br.