(46g) Structural Origin of Multiple Alkylated Cyclopentane As an Effective Lubricant

Multiple Alkylated Cyclopentanes (MACs) have been utilized as a new class of effective lubricant recently for various applications including NASA's space missions. In this study, the molecular dynamics (MD) method coupled with appropriate potential models has been used to simulate MAC molecules and construct realistic thin films sandwiched between two a-alumina surfaces. The results from the MD simulations show that, unlike symmetric molecules that can be induced by nanoscopic confinement to form layered configurations, the highly branched MAC molecules possess sufficient structural asymmetry and complexity to resist the layering tendency. Molecular interactions with the surfaces are found to turn the branches into non-trans conformations to allow parallel orientation with respect to the surfaces so that the interactions are enhanced and able to function as anchor to stabilize non-layered configuraions of the branches in a crowed environment. For comparison, the branches are severed from the cyclopentane core and the resultant mixture film becomes much more layered. These structural properties underlie the effectiveness of MACs as a new class of lubricant and provide a scientific foundation for future lubricant development.