The application of optical tweezers in oil-in-water emulsions

Oil-in-water (O/W) emulsions are widely used in industrial production, food science, petrochemicals, and other fields. Quantitative measurement of the interaction between droplets is essential for the in-depth understanding of the stability mechanism of O/W emulsions. Optical tweezers are able to accurately and quantitatively measure the interaction forces between droplets in oil-in-water emulsion systems at the microscopic scale and offer numerous advantages. In this paper, the applications of optical tweezers in oil-in-water emulsion systems are reviewed. Optical tweezer can be used to control the droplet deformation and study the aggregation phenomenon of emulsion droplets. The most important application of optical tweezer for emulsion is to measure the interaction force between emulsion droplets. Some specific examples are given to illustrate the advantages and uniqueness of optical tweezers in measuring droplets interaction forces and the methods to improve the accuracy of interaction force measurement. We summarize the study progress of optical tweezers in measuring the interaction force between droplets in recent years and discuss the challenges and prospects of measuring the interaction force between droplets based on optical tweezers.