Molecular Friction Mechanisms Across Nanofilms of a Bilayer-Forming Ionic Liquid
The prevailing paradigm in boundary lubrication asserts, in essence, that surfaces coated in amphiphiles slide past each other by way of the "slippery" exposed alkyl chains while the polar head group remains anchored at the surface. Here we show, for ionic liquid boundary lubricants, that...
| Main Authors: | , , |
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| Format: | Journal article |
| Language: | English |
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American Chemical Society
2014
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| _version_ | 1797099212056297472 |
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| author | Smith, A Parkes, M Perkin, S |
| author_facet | Smith, A Parkes, M Perkin, S |
| author_sort | Smith, A |
| collection | OXFORD |
| description | The prevailing paradigm in boundary lubrication asserts, in essence, that surfaces coated in amphiphiles slide past each other by way of the "slippery" exposed alkyl chains while the polar head group remains anchored at the surface. Here we show, for ionic liquid boundary lubricants, that the molecular mechanism of shearing is more subtle; while a monolayer on each surface gives rise to alkyl plane shearing, a bilayer on each surface shears at the ionic (nonalkyl) interface. The incorporation of water from the environment dramatically alters the shear at ionic interfaces but leaves alkyl plane shearing unaffected. Our experiments involve shearing two identical and atomically smooth surfaces past one another with films of an ionic liquid between, with subnanometer control of the film thickness and ultrasensitive shear stress resolution. With this, we uncover molecular mechanistic details relevant to boundary lubrication in general and the development of ionic liquid lubricants in particular. (Figure Presented). |
| first_indexed | 2024-03-07T05:20:30Z |
| format | Journal article |
| id | oxford-uuid:deb9185f-c50f-4fd3-aaed-03f5951cdfdb |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T05:20:30Z |
| publishDate | 2014 |
| publisher | American Chemical Society |
| record_format | dspace |
| spelling | oxford-uuid:deb9185f-c50f-4fd3-aaed-03f5951cdfdb2022-03-27T09:34:16ZMolecular Friction Mechanisms Across Nanofilms of a Bilayer-Forming Ionic LiquidJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:deb9185f-c50f-4fd3-aaed-03f5951cdfdbEnglishSymplectic Elements at OxfordAmerican Chemical Society2014Smith, AParkes, MPerkin, SThe prevailing paradigm in boundary lubrication asserts, in essence, that surfaces coated in amphiphiles slide past each other by way of the "slippery" exposed alkyl chains while the polar head group remains anchored at the surface. Here we show, for ionic liquid boundary lubricants, that the molecular mechanism of shearing is more subtle; while a monolayer on each surface gives rise to alkyl plane shearing, a bilayer on each surface shears at the ionic (nonalkyl) interface. The incorporation of water from the environment dramatically alters the shear at ionic interfaces but leaves alkyl plane shearing unaffected. Our experiments involve shearing two identical and atomically smooth surfaces past one another with films of an ionic liquid between, with subnanometer control of the film thickness and ultrasensitive shear stress resolution. With this, we uncover molecular mechanistic details relevant to boundary lubrication in general and the development of ionic liquid lubricants in particular. (Figure Presented). |
| spellingShingle | Smith, A Parkes, M Perkin, S Molecular Friction Mechanisms Across Nanofilms of a Bilayer-Forming Ionic Liquid |
| title | Molecular Friction Mechanisms Across Nanofilms of a Bilayer-Forming Ionic Liquid |
| title_full | Molecular Friction Mechanisms Across Nanofilms of a Bilayer-Forming Ionic Liquid |
| title_fullStr | Molecular Friction Mechanisms Across Nanofilms of a Bilayer-Forming Ionic Liquid |
| title_full_unstemmed | Molecular Friction Mechanisms Across Nanofilms of a Bilayer-Forming Ionic Liquid |
| title_short | Molecular Friction Mechanisms Across Nanofilms of a Bilayer-Forming Ionic Liquid |
| title_sort | molecular friction mechanisms across nanofilms of a bilayer forming ionic liquid |
| work_keys_str_mv | AT smitha molecularfrictionmechanismsacrossnanofilmsofabilayerformingionicliquid AT parkesm molecularfrictionmechanismsacrossnanofilmsofabilayerformingionicliquid AT perkins molecularfrictionmechanismsacrossnanofilmsofabilayerformingionicliquid |