Effect of droplet size on the film formation of O/W emulsion

Abstract

Purpose The purpose of this study is to reveal the underlying mechanism in film formation of oil-in-water (O/W) emulsion. Design/methodology/approach This study focuses on the film forming characteristics of O/W emulsion between the surface of a steel ball and a glass disc coated with chromium. The lubricant film thicknesses of O/W emulsion with various mechanical stirring strength were discussed, which were observed by technique of relative optical interference intensity. Findings The authors directly observed the oil pool in the contact area, finding the size of oil pool was closely related to the film-forming ability of emulsion. Enrichment phenomenon occurs in oil pool, which was caused by phase inversion. Further investigations revealed that the emulsion is stable with strong stirring strength, resulting in a smaller oil pool size and worse film forming ability. Originality/value With the wide usage of O/W emulsion in both biological and industrial systems, the ability of emulsion film formation is considered as an important factor to evaluate the lubrication effectiveness. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2022-0354/