Competitive adsorption of stearyldiethanolamine and oleic acid at the iron oxide-dodecane interface

Reducing friction between moving components in engines minimises the fuel consumption and the resulting emissions of gasoline vehicles. The lubrication of sliding surfaces can be improved by the inclusion of organic friction modifier (OFM) additives in engine oils, which adsorb at the engine surfaces and form films that reduce friction. However, their behaviour in the presence of other lubricant additives is poorly understood. In this experiment, the structure of co-adsorbed films of oleic acid and stearyldiethanolamine at the iron oxide-dodecane interface will be investigated using polarised neutron reflectometry. We will characterise the interfacial composition of the OFMs at the interface as a function of the order of introduction to the interface, oleic acid concentration and temperature.

降低发动机内运动部件间的摩擦，可减少汽油车的燃油消耗及由此产生的尾气排放。通过在发动机机油中添加有机摩擦改性剂（Organic Friction Modifier, OFM）添加剂，可改善滑动表面的润滑性能：此类添加剂会吸附于发动机部件表面并形成润滑膜，从而降低摩擦。然而，这类添加剂与其他润滑油添加剂共存时的作用机制尚未得到充分阐明。本实验将采用极化中子反射法（Polarised Neutron Reflectometry），探究油酸与硬脂基二乙醇胺在氧化铁-十二烷界面形成的共吸附膜结构。我们将针对界面引入顺序、油酸浓度与温度三个变量，表征该界面处有机摩擦改性剂的界面组分分布。