Jump to main content
Jump to site search

Issue 32, 2016
Previous Article Next Article

Effect of the environmental humidity on the bulk, interfacial and nanoconfined properties of an ionic liquid

Author affiliations

Abstract

With reference to our previous surface-force study on 1-hexyl-3-methylimidazolium ethylsulfate ([HMIM] EtSO4) using an extended surface forces apparatus, which showed an ordered structure within the nanoconfined dry ionic liquid (IL) between mica surfaces that extended up to ∼60 nm from the surface, this work focuses on the influence of the environmental humidity on the bulk, interfacial and nanoconfined structure of [HMIM] EtSO4. Infrared spectroscopy and rheometry reflect the changes in chemical and physical properties of the bulk IL due to the uptake of water when exposed to ambient humidity, while wide-angle X-ray scattering shows a mild swelling of the bulk nanostructure, and the AFM sharp tip reveals an additional surface layer at the mica–IL interface. When the water-containing [HMIM] EtSO4 is nanoconfined between two mica surfaces, no long-range order is detected, in contrast to the results obtained for the dry IL, which demonstrates that the presence of water can prevent the liquid-to-solid transformation of this IL. A combination of techniques and the calculated Bjerrum length indicate that water molecules weaken interionic electrostatic and hydrogen-bonding interactions, which lessens ion–ion correlations. Our work shows that the solid-like behavior of the nanoconfined IL strongly depends on the presence of absorbed water and hence, it has implications with regard to the correct interpretation of laboratory studies and their extension to real applications in lubrication.

Graphical abstract: Effect of the environmental humidity on the bulk, interfacial and nanoconfined properties of an ionic liquid

Back to tab navigation

Supplementary files

Publication details

The article was received on 01 jún. 2016, accepted on 12 júl. 2016 and first published on 12 júl. 2016


Article type: Paper
DOI: 10.1039/C6CP03777A
Citation: Phys. Chem. Chem. Phys., 2016,18, 22719-22730
  •   Request permissions

    Effect of the environmental humidity on the bulk, interfacial and nanoconfined properties of an ionic liquid

    L. A. Jurado, H. Kim, A. Rossi, A. Arcifa, J. K. Schuh, N. D. Spencer, C. Leal, R. H. Ewoldt and R. M. Espinosa-Marzal, Phys. Chem. Chem. Phys., 2016, 18, 22719
    DOI: 10.1039/C6CP03777A

Search articles by author

Spotlight

Advertisements