We have measured forces between mica surfaces across two hydrophobic ionic liquids with a surface forces apparatus. Both surface-adsorbed water and alkyl-chain length on the imidazolium cation influence the structure of the nanoconfined film and the dynamics of film-thickness transitions. Friction shows accumulative microslips as precursors to collective "avalanches" that abruptly reduce friction momentarily. This behavior is interpreted as a consequence of interlayer ion correlations within the 1 to 2 nm thick film; we identify this to be analogous to the friction response of crackling noise systems over a broad range of sizes.

Microslips to "avalanches" in confined, molecular layers of ionic liquids

ROSSI, ANTONELLA;
2014-01-01

Abstract

We have measured forces between mica surfaces across two hydrophobic ionic liquids with a surface forces apparatus. Both surface-adsorbed water and alkyl-chain length on the imidazolium cation influence the structure of the nanoconfined film and the dynamics of film-thickness transitions. Friction shows accumulative microslips as precursors to collective "avalanches" that abruptly reduce friction momentarily. This behavior is interpreted as a consequence of interlayer ion correlations within the 1 to 2 nm thick film; we identify this to be analogous to the friction response of crackling noise systems over a broad range of sizes.
2014
Thin-films; Alkyl chain-length; Surface forces apparatus; Friction; Ionic liquid; Water; Surface chemistry
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11584/54764
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