A Shear-Dependent Investigation of Organic Friction Modifier Films at the Iron Oxide/Oil interface

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. 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 co-adsorbed films of the OFMs oleic acid/ stearyldiethanolamine and oleic acid/glycerol monooleate will be investigated at the iron oxide-dodecane interface using sheared neutron reflectivity. We will characterise the interfacial composition of the competitive, mixed OFM systems as a function of shear rate and temperature.

润滑可保障内燃机可靠运行，同时降低尾气排放与燃油消耗。有机摩擦改进剂（Organic friction modifiers，OFMs）是发动机润滑油中常见的一类减摩添加剂，已知其可吸附于金属表面。然而，此类添加剂的确切作用机理尚未明确。为探明此类添加剂在高温及剪切条件下的作用机制，研究人员已开发出一种新型摩擦试验机装置。本实验将采用剪切中子反射技术，在氧化铁-十二烷界面处，探究两种OFMs复配吸附膜的结构：分别为油酸/硬脂基二乙醇胺体系与油酸/单油酸甘油酯体系。本研究将表征该竞争性混合OFM体系的界面组成，并分析其随剪切速率与温度的变化规律。