Wetting film dynamics and stability

TL;DR

This paper reviews how nano-bubbles on heterogeneous solid surfaces influence the stability and dynamics of wetting films, highlighting their crucial role in film lifetime and the impact of slippage effects.

Contribution

It introduces the significance of nano-bubbles and slippage effects in wetting film stability, providing new insights into their roles and mechanisms.

Findings

Nano-bubbles are key to wetting film lifetime.

Heterogeneous surfaces affect film stability.

Slippage influences capillary wave dispersion.

Abstract

Although the wetting films are similar in many aspects to other thin liquid films, there are some differences in their behavior, too. In contrast to soap and emulsion films, whose surfaces are homogeneous, solid substrates of wetting films are heterogeneous as a rule, unless special measures for their homogenization are taken. Here we mean primarily heterogeneous distribution of surface energy leading to existence of hydrophobic domains on hydrophilic surfaces and vice versa. As is known, such hydrophobic domains could play the role of gas-phase nucleation centers and it is widely accepted nowadays that nano-bubbles can be formed there. The present paper reviews the effect of nano-bubbles adhered at solid surface on stability of wetting films. It is shown that the existence of nano-bubbles is crucial for the lifetime of wetting films. Another peculiarity typical for hydrophobic solid surface, the so-called slippage effect, is also investigated and its contribution to the dispersion equation of capillary waves on wetting films is accounted for.