Ionic Liquids in Tribology

A special issue of Lubricants (ISSN 2075-4442).

Deadline for manuscript submissions: closed (31 May 2017) | Viewed by 14935

Special Issue Editor

Institute for Frontier Materials, Deakin University, Geelong, VIC 3220, Australia
Interests: tribology; ionic liquids; anti-wear additives; corrosion inhibitors; electrochemistry and surface characterisation
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In lubricated tribological applications, there is always a drive to reduce emissions, increase durability, and increase service intervals. To increase energy efficiency, there is also a need to reduce friction while maintaining, or even reducing, oil viscosity. If we are to meet these challenges, new lubricants and lubricant additives must be developed.

Ionic liquids (ILs) are a sub-class of organic salts with the arbitrary property of having a melting point below 100 °C. Liquid ILs can posses a number of useful properties, such as low volatility, non-flammability, thermal stability, broad electrochemical window, ionic conductivity and miscibility with organic compounds. At this time, ILs have predominately been used as ‘green’ solvents, but are also being investigated as possible electrolytes for batteries, as corrosion inhibitors and in tribological applications.

Ionic liquids were first proposed as lubricants in 2001, and, since that time, the number of publications has increased steadily. For use as lubricants, the low volatility, low flammability and thermal stability of ILs mean they can safely withstand the increased temperatures and pressures involved. Additionally, due to the vast array of possible anions and cations to choose from, a ‘task-specific’ IL can be designed to possess the exact properties required for lubricant applications, such as the ability to migrate and adsorb to the surface, react with the surface to form a protective tribofilm and/or be miscible in a particular base oil. Researchers initially used ILs that were easily available, but, as the area becomes more mature, the structural requirements for properties, such as miscibility in base oil or the ability to form a protective tribofilm are being discovered. This has resulted in a new phase of research in which new ILs are being designed specifically with lubricant applications in mind. This Special Issue, "Ionic Liquids in Tribology" is aimed at such current developments in ILs for tribological applications.

Dr. Anthony E. Somers
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Lubricants is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Ionic liquids
  • Lubricant additives
  • Lubricants
  • Tribofilms
  • Wear reduction
  • Friction modifier

Published Papers (3 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

1707 KiB  
Article
Ionic Liquids as Grease Base Liquids
by Robert Mozes, Peter K. Cooper, Rob Atkin and Hua Li
Lubricants 2017, 5(3), 31; https://doi.org/10.3390/lubricants5030031 - 08 Aug 2017
Cited by 11 | Viewed by 5242
Abstract
The rheological characteristics of one mineral oil and two ionic liquid (IL) based lubricating greases were explored as a function of thickener concentration. The ILs used are 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][TFSI]) and trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide ([P6,6,6,14][TFSI]), with polytetra-fluoroethylene (PTFE) particles used as thickeners. [...] Read more.
The rheological characteristics of one mineral oil and two ionic liquid (IL) based lubricating greases were explored as a function of thickener concentration. The ILs used are 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][TFSI]) and trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide ([P6,6,6,14][TFSI]), with polytetra-fluoroethylene (PTFE) particles used as thickeners. Greases with different base liquid concentrations (60–80 wt %) were investigated using small-amplitude oscillatory shear and viscous flow measurements, and contact angle measurements probed adhesion at base liquid–PTFE interfaces. Rheological properties are influenced by base liquid–PTFE adhesion and the chemical structure of the grease base liquids. With the addition of thickener, the greases generally have higher elasticity, strain resistance, and frequency independent properties. Viscometric rheological tests illustrate non-Newtonian shear-thinning behaviour for all greases. [BMIM][TFSI] based greases show the most elastic properties and strain resistance, as well as the highest initial and lowest final viscosities of the greases tested. Full article
(This article belongs to the Special Issue Ionic Liquids in Tribology)
Show Figures

Figure 1

3240 KiB  
Article
Time-Resolved Characterization of Dynamic Tribochemical Processes for Dicationic Imidazolium Ionic Liquid
by Roman Nevshupa, Marcello Conte, Silvia Guerra and Elisa Roman
Lubricants 2017, 5(3), 27; https://doi.org/10.3390/lubricants5030027 - 25 Jul 2017
Cited by 5 | Viewed by 4092
Abstract
Dynamic tribochemical processes for dicationic ionic liquid containing a geminal imidazolium cation head group bridged by a poly(ethylene glycol) and a bis(trifluoromethylsulfonyl)imide anion were studied using time-resolved mechanically stimulated gas emission mass-spectrometry (MSGE-MS). In comparison with similar monocationic imidazolium ionic liquids with short [...] Read more.
Dynamic tribochemical processes for dicationic ionic liquid containing a geminal imidazolium cation head group bridged by a poly(ethylene glycol) and a bis(trifluoromethylsulfonyl)imide anion were studied using time-resolved mechanically stimulated gas emission mass-spectrometry (MSGE-MS). In comparison with similar monocationic imidazolium ionic liquids with short alkyl or long polyether side chains, the dicationic ionic liquid had a lower coefficient of friction on Ti6Al4V alloy and smoother behavior. The analysis of volatile decomposition products suggested multiple tribochemical reactions in which both anionic and cationic moieties are involved. The tribochemical degradation of cations was mainly through the detachment of the side and bridging chains from the imidazolium head groups. The absence of volatile products containing nitrogen implies that the imidazole group remained unchanged. Hydrogen and water desorption were attributed to the reactions of hydrogen fluoride being a product of anion degradation with titanium and titanium oxide, respectively. Full article
(This article belongs to the Special Issue Ionic Liquids in Tribology)
Show Figures

Graphical abstract

Review

Jump to: Research

1361 KiB  
Review
Ionanocarbon Lubricants. The Combination of Ionic Liquids and Carbon Nanophases in Tribology
by María-Dolores Avilés, Noelia Saurín, José Sanes, Francisco-José Carrión and María-Dolores Bermúdez
Lubricants 2017, 5(2), 14; https://doi.org/10.3390/lubricants5020014 - 23 May 2017
Cited by 29 | Viewed by 5165
Abstract
The present overview will focus on the tribological applications of what we have called ionanocarbon lubricants, that is, the combination of carbon nanophases (graphene, carbon nanotubes, nanodiamonds, carbon nanodots) and room-temperature ionic liquids in new dispersions, blends, or modified nanostructures and their use [...] Read more.
The present overview will focus on the tribological applications of what we have called ionanocarbon lubricants, that is, the combination of carbon nanophases (graphene, carbon nanotubes, nanodiamonds, carbon nanodots) and room-temperature ionic liquids in new dispersions, blends, or modified nanostructures and their use in tribology, lubrication, and surface engineering as friction-reducing, antiwear, and surface-protecting agents in thin films and composite materials. Further research lines and factors that limit the practical applications of the outstanding research results are also highlighted. The very recent results in these lines of research make this a necessary brief review. Full article
(This article belongs to the Special Issue Ionic Liquids in Tribology)
Show Figures

Figure 1

Back to TopTop