Influence of surface-active agents on the dynamic wetting film rupture: Gas migration and surface nanobubbles formation

In this research, precise motion control and synchronized high-speed microscopic dual-wavelength interferometry were employed to investigate the impact of surface-active components on the rupture behavior of wetting films. The findings unveiled a novel mechanism for wetting film rupture at hydrophobic interfaces, propelled by gas migration towards the solid-liquid interface, resulting in the nucleation and growth of surface nanobubble. Salt ions accelerate film rupture by reducing electrostatic interactions and enhancing gas transfer, whereas surfactant adsorption immobilizes the gas-liquid interface through the Marangoni effect, thereby postponing rupture by impeding gas migration and surface nanobubble formation. Furthermore, surfactants influence the kinetics of three-phase contact line formation, where variations in molecular structure, solubility, and ionic properties contributing to differing levels of friction, and thereby affecting the overall dynamics of wetting films. ● High-speed dual-wavelength interferometry with precise motion control was employed. ● Dynamic wetting film rupture caused by gas migration was observed and analyzed. ● Surfactants delay wetting film rupture by reducing drainage rate and gas migration. ● Salt ions accelerate wetting film rupture by enhancing gas migration and drainage. ● Surfactants significantly influence triple-phase contact dynamic of wetting film.