Molecular dynamics simulations to aid the rational design of organic friction modifiers
| Autor: | Sarah L. Hinchley, Andrew Parkin, Simon Parsons, James E. Davidson, S.G. Harris, Peter A. Tasker |
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| Rok vydání: | 2005 |
| Předmět: |
Models
Molecular Friction Hydrogen bond Chemistry Glyceride Intermolecular force Thermodynamics Friction modifier Hydrogen Bonding Computer Graphics and Computer-Aided Design Glycerides Solvent Molecular dynamics Structure-Activity Relationship Surface-Active Agents Models Chemical Computational chemistry Drug Design Monolayer Materials Chemistry Molecule Computer Simulation Physical and Theoretical Chemistry Spectroscopy |
| Zdroj: | Journal of molecular graphicsmodelling. 25(4) |
| ISSN: | 1093-3263 |
| Popis: | Molecular dynamics simulations were performed under conditions of constant volume and temperature and of constant pressure and temperature to elucidate the structure activity relationships of a series of non-ionic surfactant molecules derived from vegetable fat and employed as friction modifiers in commercial engine oils. The simulations show the extent to which intermolecular hydrogen bonding is important in determining the stability of the monolayer formed by the surfactant molecules and show that mono-alkanoyl glyceride molecules are able to pack more efficiently, forming significantly more intermolecular hydrogen bonds and occupying approximately half the volume needed by di-alkanoyl glyceride molecules. Density profiles are presented which show significant mixing of the hydrophobic tail groups and a non-polar solvent. The distribution of torsion angles in the tail groups shows that the conformation is consistent with a liquid at finite temperature rather than a crystal structure. The measured friction coefficients of equimolar solutions of the glycerides show that the efficacy as friction modifiers varies in the order mono-, di- and the tri-oleyl glyceride, which is consistent with the efficacy of film formation predicted by the molecular dynamics calculations. |
| Databáze: | OpenAIRE |
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