Sum Frequency Generation Study of the Room-Temperature Ionic Liquids/Quartz Interface

2006 ◽  
Vol 110 (12) ◽  
pp. 6213-6223 ◽  
Author(s):  
Casey Romero ◽  
Steven Baldelli
Keyword(s):  
Ionic Liquids ◽  
Room Temperature ◽  
Sum Frequency Generation ◽  
Room Temperature Ionic Liquids ◽  
Sum Frequency ◽  
Frequency Generation

scholarly journals Competitive Adsorption of Ionic Liquids Versus Friction Modifier and Anti-Wear Additive at Solid/Lubricant Interface—Speciation with Vibrational Sum Frequency Generation Spectroscopy

Lubricants ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 98
Author(s):  
Dien Ngo ◽  
Xin He ◽  
Huimin Luo ◽  
Jun Qu ◽  
Seong H. Kim
Keyword(s):  
Ionic Liquids ◽  
Competitive Adsorption ◽  
Silica Surface ◽  
Sum Frequency Generation ◽  
Lubricant Additives ◽  
Solid Base ◽  
Friction Modifier ◽  
Base Oil ◽  
Sum Frequency ◽  
Frequency Generation

A modern lubricant contains various additives with different functionalities and the interactions or reactions between these additives could induce synergistic or antagonistic effects in tribological performance. In this study, sum frequency generation (SFG) spectroscopy was used to investigate competitive adsorption of lubricant additives at a solid/base oil interface. A silica substrate was used as a model solid surface. The lubricant additives studied here included two oil-soluble ionic liquids (ILs, [N888H][DEHP] and [P8888][DEHP]), an antiwear additive (secondary ZDDP), an organic friction modifier (OFM), and a dispersant (PIBSI). Our results showed that for mixtures of ZDDP and IL in a base oil (PAO4), the silica surface is dominated by the IL molecules. In the cases of base oils containing OFM and IL, the silica/lubricant interface is dominated by OFM over [N888H][DEHP], while it is preferentially occupied by [P8888][DEHP] over OFM. The presence of PIBSI in the mixture of PAO4 and IL leads to the formation of a mixed surface layer at the silica surface with PIBSI as a major component. The SFG results in this investigation provide fundamental insights that are helpful to design the formulation of new lubricant additives of desired properties.

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