Exploring the effects of approach velocity on depletion force and coalescence in oil-in-water emulsions

An emulsion is a thermodynamically unstable system consisting of at least two immiscible liquid phases, one of which is dispersed in the other in the form of droplets of varying size. Most studies on emulsions have focused on the behaviour of emulsion droplets with diameter from similar to 50 mu m and upwards. However, the properties of smaller droplets may be highly relevant in order to understand the behaviour of emulsions, including their performance in numerous applications within the fields of food, industry, and medical science. The relatively long life-time and small size of these droplets compared to other emulsion droplets, make them suited for optical trapping and micromanipulation technologies. Optical tweezers have previously shown potential in the study of stabilized emulsions. Here we employ optical tweezers to examine unstable oil-in-water emulsions to determine the effects of system parameters on depletion force and coalescence times.

Automated summary

An emulsion is a thermodynamically unstable system consisting of at least two immiscible liquid phases, with one dispersed as droplets of varying size in the other. While most studies on emulsions have focused on larger droplets, the properties of smaller droplets are crucial for understanding emulsion behavior in various applications. Optical tweezers can be used to examine unstable emulsions and study the effects of system parameters on depletion force and coalescence times.