Appointing the optimal surfactant concentration for efficient 2D-laminar O/W emulsion flow

Abstract

Ensuring emulsion stability during flow is crucial across industries such as food production, petroleum, and pharmaceuticals, where optimizing emulsifier use enhances stability, reduces costs, and extends shelf life. Despite its importance, a clear approach that considers the mechanisms governing droplet size during transport remains an open area for improvement. In this study, we apply a previously proposed model to estimate the surfactant concentration required to ensure emulsion stability under flow conditions. We show that the parameters employed in the Langmuir isotherm successfully capture the key trends across most regions of the experimental data. Furthermore, we propose that a precise characterization of the coalescence dynamics of flowing droplets must account for both hydrodynamic and steric effects. By considering surfactants of different natures, we demonstrate the model's versatility and practical relevance for diverse industrial applications. We discuss our predictions compared with experimental reports and hydrodynamic theory, finding good alignment.