In-Situ Adsorption of Friction Modifier Additives: A Combined QCM-D and CLSM Study

Understanding the adsorption mechanisms of friction modifier additives is a widely studied topic and of high interest for the development of future lubricants. Being able to observe the adsorption in-situ in the lubricant as function of temperature or tribological stressing is particularly helpful. For this reason we developed a combined quartz crystal microbalance with dissipation (QCM-D) and confocal laser scanning microscopy (CLSM) setup that allow to determine the adsorbed mass and visualize the additive molecules by fluorescence. Experiments using an organic friction modifier showed that the additive forms droplets that adsorb on the iron oxide surface.