8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P7.24Thu 811:10-14:00Molecular dynamics study of long-chain alkyl amideadsorption under shear conditionsMichael Doig 11 University of Edinburgh, Joseph Black Building, West Mains Road EH9 3JJ, Edinburgh,United KingdomLubricant oils play important roles in a wide range of industrial and mechanical processes, wherethey are used to reduce both friction and wear between moving surfaces. Surface-active moleculesadded to lubricant oils can adsorb onto surfaces and enhance these effects. Molecular dynamicssimulations have been used to investigate the microscopic structure and dynamics in adsorbedsurface films of long chain alkyl amides in squalane (C 30 H 62 ) base oil, on a range of surfaces includingalumina (alpha-Al 2 O 3 ) and iron oxide (alpha-Fe 2 O 3 ). The effects of temperature, pressure,and shear rate on the structure and stability of the adsorbed surface films have been studied. Theresults show how the orientations and surface stability of the adsorbed surface active moleculesvary with changes in these conditions. This is important as the structure of the adsorbed film canhave a significant effect on the performance of a lubricant and hence the operational conditionsunder which it is effective.24