Slippery-Sticky Transition of Interfacial Fluid Slip

TL;DR

This study uses molecular dynamics simulations to explore how temperature affects interfacial fluid slip, revealing two distinct thermal behaviors and a transition point influenced by fluid-solid interactions.

Contribution

It introduces a comprehensive analysis of slip behavior transitions at the fluid-solid interface and validates an analytical model predicting these phenomena.

Findings

Identification of slippery and sticky slip regimes

Convergence to finite slip lengths at higher temperatures

Validation of an analytical model for slip transition

Abstract

The influence of temperature on interfacial fluid slip, as measured by molecular-dynamics simulations of a Couette flow comprising a Lennard-Jones fluid and rigid crystalline walls, is examined as a function of the fluid-solid interaction strength. Two different types of thermal behavior are observed, namely, the slippery and sticky cases. The first is characterized by a steep and unlimited increase of the slip length at low temperatures, while the second presents a vanishing slip length in this regime. As the temperature increases in relation to a characteristic value, both cases converge to finite slip lengths. A recently proposed analytical model is found to well describe both thermal behaviors, also predicting the slippery-sticky transition that occurs at a critical value of the fluid-solid interaction parameter, for which, according to the model, fluid particles experience a smooth average energy landscape at the interface.