Rubber Friction -A Molecular Picture

Understanding the relationship between adhesion, friction and the interfacial structure has been of significant interest for many years. Most tribological experiments involve measuring friction and adhesion values to develop a molecular model to explain the macroscopic results. Here, we have used surface sensitive infrared-visible sum frequency generation spectroscopy (SFG) to study the interface between elastomer and solid surfaces. SFG is a second order nonlinear optical technique that provides information on the chemical identity; orientation and concentration of the molecules at the interface. We have designed a friction cell to probe the changes in the interfacial structure during sliding using a femto-second laser spectroscopy. These results will be presented.