Investigation of Headgroup Chemistry-Induced Changes on the Formation of Organic Friction Modifier Films at the Iron Oxide/Oil Interfaces

Lubrication ensures the reliable operation of combustion engines whilst also offering a reduction in emissions and fuel consumption. Organic friction modifiers(OFMs) are a common class of friction-reducing additives included in engine lubricants, and are known to adsorb at metal surfaces. However, the exact mechanism by which they operate has yet to be defined. In order to utilise these compounds optimally, this mechanism must be precisely understood, informing the next generation of OFMs. To understand how these additives function at elevated temperatures and under shear, a novel tribometer rig has been developed. In this experiment, the structure of a range of OFM candidates will be investigated at the iron oxide-dodecane interface using static and sheared neutron reflectivity. The compounds we will study are related to Ethomeen 18/12 (E1812), a successful OFM candidate that we have characterised in our previous experiments. We will investigate how changes in headgroup nature affect the interfacial composition of OFM films as a function of shear rate and chemistry type, and how the resulting structures compare to that of adsorbed E1812. This work will exploit the use of INTER and deuteration to understand adsorption mechanisms on hematite.