Nanoscale Organic−Inorganic Hybrid Lubricants

Daniel Kim, Lynden A. Archer

Research output: Contribution to journalArticlepeer-review

107 Scopus citations

Abstract

Silica (SiO2) nanoparticles densely grafted with amphiphilic organic chains are used to create a family of organic-inorganic hybrid lubricants. Short sulfonate-functionalized alkylaryl chains covalently tethered to the particles form a dense corona brush that stabilizes them against aggregation. When these hybrid particles are dispersed in poly-α-olefin (PAO) oligomers, they form homogeneous nanocomposite fluids at both low and high particle loadings. By varying the volume fraction of the SiO2 nanostructures in the PAO nanocomposites, we show that exceptionally stable hybrid lubricants can be created and that their mechanical properties can be tuned to span the spectrum from simple liquids to complex gels. We further show that these hybrid lubricants simultaneously exhibit lower interfacial friction coefficients, enhanced wear and mechanical properties, and superior thermal stability in comparison with either PAO or its nanocomposites created at low nanoparticle loadings. Profilometry and energy dispersive X-ray spectroscopic analysis of the wear track show that the enhanced wear characteristics in PAO-SiO2 composite lubricants originate from two sources: localization of the SiO2 particles into the wear track and extension of the elastohydrodynamic lubrication regime to Sommerfeld numbers more than an order of magnitude larger than for PAO. © 2011 American Chemical Society.
Original languageEnglish (US)
Pages (from-to)3083-3094
Number of pages12
JournalLangmuir
Volume27
Issue number6
DOIs
StatePublished - Mar 15 2011
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-C1-018-02
Acknowledgements: This work was supported by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST), and by SUMMIT Lubricants, Inc. (ID071210). The authors are grateful to Chevron-Phillips for Synfluid PAO and to Oil-Chem Technologies for supplying the material XSA-1416.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

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