Common Features of 'Rag'' Layers in Water-in-Crude Oil Emulsions with Different Stability. Possible Presence of Spontaneous Emulsification

摘要

Aging W/O emulsions with various stabilities brake into "rags'' - fragments with uneven shapes. Individual "rags'' combine into a separate "rag'' layer below supernatant oil. In the "rag'' material, the continuous oil phase is enriched in heavy constituents, while the disperse phase contains two populations of water drops. Larger drops are formed by mechanical dispersion during emulsification, as indicated by their log-normal number size distributions. Smaller droplets possess exponential number size distributions, indicating a possibility of their spontaneous nucleation. The latter conclusion is supported by microscopic observation of spontaneous appearance of small droplets at a stationary oil-water interface.