In this manuscript, we explore the adsorption of mixed bovine serum albumin (BSA) and b-casein at the interface between the fluorinated oil Novec 7500 (relevant to microdroplet platforms for biotechnologies) and phosphate buffer saline. We characterise the impact such assemblies have on interfacial shear mechanics and correlate these changes with surface composition. We then characterise the nanostructure and diffusion of assemblies of both isolated proteins via neutron reflectometry and fluorescence recovery after photobleaching (FRAP), respectively. Finally, we explore the impact of chemical crosslinking and protein exchange on interfacial mechanics.