Emulsions, characterized as a metastable dispersion of one liquid into a second one in the presence of surface-active agents, have complex rheology that interests both physicists and industries. Depending on the volume fraction of the dispersed phase ($\phi$), emulsions can display both solid-like and liquid-like behavior. Rheometrical measurements of complex fluids usually yield several flow curves, each corresponding to a certain volume fraction. Scaling analysis assists in investigating the fundamental traits of those flow curves by rescaling the rheometrical data onto several master curves described by a few non-dimensional variables.

Whereas experiments successfully scaled the data onto master curves are usually of three-dimensional complex fluids, many numerical simulations are of low-cost two-dimensional flows, lacking direct referable experimental data. Additionally, scenarios involving droplets, bubbles, and particles trapped at the interface of two fluids inherently constitute a two-dimensional system. Motivated by these considerations, the project aims to measure the rheology of emulsion monolayers.

A cylindrical Couette ring configuration was built to facilitate the generation of monolayers and rheometrical measurements. The image processing method was developed to deal with three distinct scenarios, high $\phi$, medium $\phi$, and low $\phi$, depending on the concentration of droplets. The steady velocity profiles and the averaged packing fractions were acquired through image analysis. Subsequently, the local rheology was deduced and compared with the macroscopic rheological measurement at various packing fractions. While the densely packed emulsion monolayer is a shear-thinning yield stress material, the spatial cooperativity (non-local effect) and capillary force (wall effect) were found to have a profound influence on the rheology.