Water in Ionic Liquid Lubricants: Friend and Foe
File(s)
Supporting information
Accepted version
Author(s)
Fajardo, OY
Bresme, F
Kornyshev, AA
Urbakh, M
Type
Journal Article
Abstract
To a greater or lesser extent, most room-temperature ionic liquids (RTILs) absorb water from humid air. Penetration of water into the lubricating nanoscale film may affect its equilibrium structure and dynamic properties and thus influence the ability of RTILs as lubricants to reduce friction between solid surfaces. Here we investigate the impact of hydration on lubrication using nonequilibrium molecular dynamics simulations. Water adsorption changes both the ionic liquid molecules’ orientation and the slip conditions at the solid–liquid interfaces, resulting in a reduced resistance against squeezing-out of the lubricant by an external load. For the same normal load, the film becomes thinner when water is present. We show that even small amounts of water can screen the electrostatic interactions between the ions, making RTILs more “fluid” and compressible and hence less resistant to external stress. The impact that screening has on friction involves several aspects that are systematically analyzed in this paper.
Date Issued
2017-06-21
Date Acceptance
2017-06-21
Citation
ACS NANO, 2017, 11 (7), pp.6825-6831
ISSN
1936-0851
Publisher
American Chemical Society
Start Page
6825
End Page
6831
Journal / Book Title
ACS NANO
Volume
11
Issue
7
Copyright Statement
© 2017 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Nano, after peer review and technical editing by the publisher. To access the final edited and published work see https://dx.doi.org/10.1021/acsnano.7b01835
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000406649700030&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Physical Sciences
Technology
Chemistry, Multidisciplinary
Chemistry, Physical
Nanoscience & Nanotechnology
Materials Science, Multidisciplinary
Chemistry
Science & Technology - Other Topics
Materials Science
ionic liquids
hydration
lubrication
nanoscale films
screening
MOLECULAR-DYNAMICS SIMULATIONS
FRICTION
CONFINEMENT
LUBRICITY
SURFACES
MD Multidisciplinary
Publication Status
Published