The Influence of Surface-Active Material on the Properties of Air Bubbles at the Air/Sea Interface

摘要

The lifetimes of single air bubbles were measured at water surfaces covered by various monomolecular films. Simultaneous measurements of bubble lifetime vs molecular area and film pressure vs area were made using air bubbles of various diameters. As the film pressure increased, the bubble lifetime passed through a maximum at about 1 dyne/cm and decreased at higher pressure with closer molecular packing. Mechanisms to account for this effect were based on surface tension gradient flow and dilational viscous forces within the film. The bubble stability data were used to describe molecular interactions and orientations within the stabilizing monolayer. The lifetimes of bubbles at an air/sea interface were shown to be dependent upon the concentration of organic material in the water and the surface-chemical condition of the sea surface. The presence of a coherent surface film substantially reduced bubble stability, especially at elevated film pressures. (Author)