Understanding the effect of the base oil on the physical adsorption process of organic additives using molecular dynamics

TL;DR

This study uses molecular dynamics to investigate how different base oils influence the initial adsorption process of organic friction modifiers, revealing that oil structure affects adsorption time and other factors beyond chain matching.

Contribution

It provides new insights into the molecular-level adsorption process of OFMs in various base oils, highlighting effects beyond traditional chain matching considerations.

Findings

Adsorption time varies with base oil structure

Base oil influences adsorption beyond chain matching

Molecular dynamics effectively models initial adsorption processes

Abstract

Organic friction modifiers (OFMs) are widely added to oil to reduce the boundary friction in many kinds of lubricants such as vehicle engine oils. At the contact area in machine elements, the OFMs form a self-assembled organic monolayer. Although the friction properties of the monolayer are widely studied on a molecular level, the formation process is not well-known. In this study, the initial adsorbing process of additive molecules in explicit base oil molecules are calculated using molecular dynamics. The adsorption time depends on the structure of the base oils. Another effect of the base oil other than "chain matching" is found.