# Multiscale simulation on shearing transitions of thin-film lubrication with multi-layer molecules

## TL;DR

This paper uses a multiscale simulation to study shearing transitions in thin-film lubrication, revealing how coupling strength and load affect slip behaviors and film thickness, aligning with experimental observations.

## Contribution

It introduces a multiscale method to analyze shearing transitions in multi-layer molecular thin films, highlighting the effects of coupling strength and load on tribological behavior.

## Key findings

- Three types of interlayer slip match experimental results.
- Tribological behaviors are insensitive to small coupling strength.
- Effective film thickness increases with larger coupling strength, decreases with load.

## Abstract

Shearing transitions of multi-layer molecularly thin-film lubrication systems in variations of the film-substrate coupling strength and the load are studied by using a multiscale method. Three kinds of the interlayer slips found in decreasing the coupling strength are in qualitative agreement with experimental results. Although tribological behaviors are almost insensitive to the smaller coupling strength, they and the effective film thickness are enlarged more and more as the larger one increases. When the load increases, the tribological behaviors are similar to those in increasing coupling strength, but the effective film thickness is opposite.