Activities per year
Abstract
The liquid–vacuum interfaces of a series of ionic liquids (ILs) containing 1-alkyl-1-methylpyrrolidinium ([Cnmpyrr]+) cations of different alkyl chain lengths have been studied by reactive-atom scattering with laser-induced fluorescence detection (RAS-LIF) and molecular dynamics (MD) simulations. A direct, quantitative comparison has been performed between [Cnmpyrr]+ and the previously better-characterized 1-alkyl-3-methylimidazolium ([Cnmim]+) ILs with the same chain lengths, n, and common anion, bis(trifluoromethylsulfonyl)imide ([Tf2N]−). Both RAS-LIF experiments, using O(3P) as the projectile and monitoring OH yield, and MD simulations indicate that the coverage of the surface by alkyl chains is almost independent of the identity of the cation headgroup. Moreover, the potentially abstractable H atoms of the saturated pyrrolidinium ring do not contribute appreciably to the experimental OH yield. In both these senses, therefore, the headgroup is “hidden” from the probe particles approaching from vacuum. More predictably, the alkyl coverage depends strongly and nonstoichiometrically on the length of the alkyl chain, n, for either cation. These results imply the presence of an alkyl-rich layer on the surface formed by preferential orientation of the cations to expose their chains to the vacuum phase. We suggest that the lack of dependence of the packing density of this layer on cation type results from compensating effects of charge density and steric blocking.
Original language | English |
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Pages (from-to) | 27369–27379 |
Number of pages | 11 |
Journal | Journal of Physical Chemistry C |
Volume | 120 |
Issue number | 48 |
Early online date | 7 Nov 2016 |
DOIs | |
Publication status | Published - 8 Nov 2016 |
Bibliographical note
© 2016 American Chemical Society. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for detailsProfiles
Activities
- 3 Conference participation
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ISIS Neutron and Muon Science and User Meeting 2018
John Martin Slattery (Participant)
25 Apr 2018 → 27 Apr 2018Activity: Participating in or organising an event › Conference participation
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655. WE-Heraeus-Seminar: Surfaces and Interfaces of Ionic Liquids
John Martin Slattery (Participant)
3 Dec 2017 → 6 Dec 2017Activity: Participating in or organising an event › Conference participation
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Ionic liquids: from fundamental properties to practical applications - Faraday Discussion
John Martin Slattery (Speaker)
11 Sept 2017 → 13 Sept 2017Activity: Participating in or organising an event › Conference participation
Projects
- 1 Finished
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Exploring the surface structure of ionic liquids and correlating this with key applications
Slattery, J. M. & Bruce, D. W.
2/12/13 → 1/12/16
Project: Research project (funded) › Research