MICROFLUIDIC APPROACHES FOR MEASURING THE INTERFACIAL TENSION IN FLUID-FLUID SYSTEMS: A CONCISE REVIEW

Abstract

Interfacial tension (IFT) between two fluids plays a crucial role in many processes at the industrial level, such as dairy products, paints, pharmaceuticals, cosmetics, and oil recovery. Consequently, especially from the application point of view, a precise and rapid measurement of the IFT is crucial. The traditional methods of IFT measurement, including tensiometry, remain popular as these are relatively straightforward to implement and do not necessitate high throughput techniques. However, most traditional methods are limited to be utilized for small volumes of precious solutions. Additionally, it is challenging to miniaturize the devices for point-of-care applications. These issues have served as a perpetual motivation to develop novel techniques for the IFT measurements. In this context, over the past two decades, a wide range of microfluidic tensiometry techniques have been established to confront, alleviate, and mitigate the concerns related to traditional tensiometry. In this review, I critically assess the progress in these novel microfluidic approaches for the IFT measurement, intending to update the readers with these newly developed techniques. KEY WORDS: microfluidics, tensiometry, interfacial tension, surfactants, droplet deformation