3-Dimensional atomic scale structure of the ionic liquid-graphite interface elucidated by AM-AFM and quantum chemical simulations

Alister J. Page, Aaron Elbourne, Ryan Stefanovic, Matthew A. Addicoat, Gregory G. Warr, Kislon Voïtchovsky, Rob Atkin

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

In situ amplitude modulated atomic force microscopy (AM-AFM) and quantum chemical simulations are used to resolve the structure of the highly ordered pyrolytic graphite (HOPG)-bulk propylammonium nitrate (PAN) interface with resolution comparable with that achieved for frozen ionic liquid (IL) monolayers using STM. This is the first time that (a) molecular resolution images of bulk IL-solid interfaces have been achieved, (b) the lateral structure of the IL graphite interface has been imaged for any IL, (c) AM-AFM has elucidated molecular level structure immersed in a viscous liquid and (d) it has been demonstrated that the IL structure at solid surfaces is a consequence of both thermodynamic and kinetic effects. The lateral structure of the PAN-graphite interface is highly ordered and consists of remarkably well-defined domains of a rhomboidal superstructure composed of propylammonium cations preferentially aligned along two of the three directions in the underlying graphite lattice. The nanostructure is primarily determined by the cation. Van der Waals interactions between the propylammonium chains and the surface mean that the cation is enriched in the surface layer, and is much less mobile than the anion. The presence of a heterogeneous lateral structure at an ionic liquid-solid interface has wide ranging ramifications for ionic liquid applications, including lubrication, capacitive charge storage and electrodeposition.

Original languageEnglish
Pages (from-to)8100-8106
Number of pages7
JournalNanoscale
Volume6
Issue number14
DOIs
Publication statusPublished - 21 Jul 2014
Externally publishedYes

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Ionic Liquids
Graphite
Ionic liquids
Atomic force microscopy
Cations
Positive ions
Nitrates
Image resolution
Electrodeposition
Lubrication
Anions
Monolayers
Nanostructures
Negative ions
Thermodynamics
Kinetics
Liquids

Cite this

Page, Alister J. ; Elbourne, Aaron ; Stefanovic, Ryan ; Addicoat, Matthew A. ; Warr, Gregory G. ; Voïtchovsky, Kislon ; Atkin, Rob. / 3-Dimensional atomic scale structure of the ionic liquid-graphite interface elucidated by AM-AFM and quantum chemical simulations. In: Nanoscale. 2014 ; Vol. 6, No. 14. pp. 8100-8106.
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3-Dimensional atomic scale structure of the ionic liquid-graphite interface elucidated by AM-AFM and quantum chemical simulations. / Page, Alister J.; Elbourne, Aaron; Stefanovic, Ryan; Addicoat, Matthew A.; Warr, Gregory G.; Voïtchovsky, Kislon; Atkin, Rob.

In: Nanoscale, Vol. 6, No. 14, 21.07.2014, p. 8100-8106.

Research output: Contribution to journalArticle

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