Viscosity ratio: A key factor for control of oil drop size distribution in effervescent atomization of oil-in-water emulsions

► Impact of effervescent atomization on oil-in-water emulsions was investigated. ► Relevance of elongational stresses on drop breakup was proven. ► Viscosity ratio of disperse phase to emulsion proved to be a key factor for drop breakup in atomization. ► A maximum breakup was found for a viscosity ratio between 0.5 and 1. ► Control of viscosity ratio allows for efficient control of drop breakup.