Nanotribology of Ionic Liquids: Transition to Yielding Response in Nanometric Confinement with Metallic Surfaces
Room-temperature ionic liquids (RTILs) are molten salts which exhibit unique physical and chemical properties, commonly harnessed for lubrication and energy applications. The pure ionic nature of RTIL leads to strong electrostatic interactions among the liquid, furthermore exalted in the presence of...
Main Authors: | , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
American Physical Society
2020-03-01
|
Series: | Physical Review X |
Online Access: | http://doi.org/10.1103/PhysRevX.10.011068 |
id |
doaj-d35d8a6da81b4cd7ab90dabe8fc3a7e8 |
---|---|
record_format |
Article |
spelling |
doaj-d35d8a6da81b4cd7ab90dabe8fc3a7e82020-11-25T02:07:43ZengAmerican Physical SocietyPhysical Review X2160-33082020-03-0110101106810.1103/PhysRevX.10.011068Nanotribology of Ionic Liquids: Transition to Yielding Response in Nanometric Confinement with Metallic SurfacesAntoine LainéAntoine NiguèsLydéric BocquetAlessandro SiriaRoom-temperature ionic liquids (RTILs) are molten salts which exhibit unique physical and chemical properties, commonly harnessed for lubrication and energy applications. The pure ionic nature of RTIL leads to strong electrostatic interactions among the liquid, furthermore exalted in the presence of interfaces and confinement. In this work, we use a tuning-fork-based dynamic surface force tribometer, which allows probing both the rheological and the tribological properties of RTIL films confined between a millimetric sphere and a surface, over a wide range of confinements. When the RTIL is confined between metallic surfaces, we see evidence of an abrupt change of its rheological properties below a threshold confinement. This is reminiscent of a recently reported confinement-induced capillary freezing, here observed with a wide contact area. In parallel, we probe the tribological response of the film under imposed nanometric shear deformation and unveil a yielding behavior of the interfacial solid phase below this threshold confinement. This is characterized by a transition from an elastic to a plastic regime, exhibiting striking similarities with the response of glassy materials. This transition to yielding of the RTIL in metallic confinement leads overall to a reduction in friction and offers a self-healing protection of the surfaces avoiding direct contact, with obvious applications in tribology.http://doi.org/10.1103/PhysRevX.10.011068 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Antoine Lainé Antoine Niguès Lydéric Bocquet Alessandro Siria |
spellingShingle |
Antoine Lainé Antoine Niguès Lydéric Bocquet Alessandro Siria Nanotribology of Ionic Liquids: Transition to Yielding Response in Nanometric Confinement with Metallic Surfaces Physical Review X |
author_facet |
Antoine Lainé Antoine Niguès Lydéric Bocquet Alessandro Siria |
author_sort |
Antoine Lainé |
title |
Nanotribology of Ionic Liquids: Transition to Yielding Response in Nanometric Confinement with Metallic Surfaces |
title_short |
Nanotribology of Ionic Liquids: Transition to Yielding Response in Nanometric Confinement with Metallic Surfaces |
title_full |
Nanotribology of Ionic Liquids: Transition to Yielding Response in Nanometric Confinement with Metallic Surfaces |
title_fullStr |
Nanotribology of Ionic Liquids: Transition to Yielding Response in Nanometric Confinement with Metallic Surfaces |
title_full_unstemmed |
Nanotribology of Ionic Liquids: Transition to Yielding Response in Nanometric Confinement with Metallic Surfaces |
title_sort |
nanotribology of ionic liquids: transition to yielding response in nanometric confinement with metallic surfaces |
publisher |
American Physical Society |
series |
Physical Review X |
issn |
2160-3308 |
publishDate |
2020-03-01 |
description |
Room-temperature ionic liquids (RTILs) are molten salts which exhibit unique physical and chemical properties, commonly harnessed for lubrication and energy applications. The pure ionic nature of RTIL leads to strong electrostatic interactions among the liquid, furthermore exalted in the presence of interfaces and confinement. In this work, we use a tuning-fork-based dynamic surface force tribometer, which allows probing both the rheological and the tribological properties of RTIL films confined between a millimetric sphere and a surface, over a wide range of confinements. When the RTIL is confined between metallic surfaces, we see evidence of an abrupt change of its rheological properties below a threshold confinement. This is reminiscent of a recently reported confinement-induced capillary freezing, here observed with a wide contact area. In parallel, we probe the tribological response of the film under imposed nanometric shear deformation and unveil a yielding behavior of the interfacial solid phase below this threshold confinement. This is characterized by a transition from an elastic to a plastic regime, exhibiting striking similarities with the response of glassy materials. This transition to yielding of the RTIL in metallic confinement leads overall to a reduction in friction and offers a self-healing protection of the surfaces avoiding direct contact, with obvious applications in tribology. |
url |
http://doi.org/10.1103/PhysRevX.10.011068 |
work_keys_str_mv |
AT antoinelaine nanotribologyofionicliquidstransitiontoyieldingresponseinnanometricconfinementwithmetallicsurfaces AT antoinenigues nanotribologyofionicliquidstransitiontoyieldingresponseinnanometricconfinementwithmetallicsurfaces AT lydericbocquet nanotribologyofionicliquidstransitiontoyieldingresponseinnanometricconfinementwithmetallicsurfaces AT alessandrosiria nanotribologyofionicliquidstransitiontoyieldingresponseinnanometricconfinementwithmetallicsurfaces |
_version_ |
1724930120185020416 |