Influence of Surface Hydrophobicity on the Motion Behavior of Particles at Gas-Liquid Interface.

Based on the calculation of interaction force between particles, the analysis of interfacial agglomeration microstructure, the analysis of agglomeration reorganization process and the calculation of equilibrium force acting on particles, the oscillation behavior of particles with different hydrophobicity after the coalescence of bubble and particle monolayer at gas-liquid interface was systematically studied by using a modified L-B trough and a high-speed dynamic microscopic test device. The results showed that, with the same adsorption density of interfacial particles, dense aggregates were formed more easily for the particles with low hydrophobicity (contact angle = 43°), while the aggregates formed by the particles with high hydrophobicity (contact angle=75°) were looser. The interface oscillation can be induced by the coalescence of bubble and particle monolayer. Under this effect, the agglomerates on the interface were continuously reorganized under the influence of the surface pressure gradient and the oscillation wave, and finally the dispersion of the interface particles became more uniform, which was very similar to the Gibbs-Marangoni effect of stabilizing the liquid film by foaming agent molecules. The horizontal drag force, inertia force and the interaction force between particles played a key role in the process of interfacial agglomeration reorganization. Under the same test conditions, the instantaneous velocity and the mean square displacement (MSD) of the particles with low hydrophobicity were significantly larger than those of the particles with high hydrophobicity due to the additional vertical upward capillary force, which means that the oscillation intensity of particles with low hydrophobicity was more intense, the amplitude was larger, and the desorption probability was higher. [ABSTRACT FROM AUTHOR]