b-casein in the feed solution led to 50% assembly at liquid-liquid interfaces; Figure ). Such behaviour is well documented for co-assembly of proteins at liquid interfaces, in particular in the case of b-casein, although the dominance of b-casein adsorption to Novec 7500 interfaces was more pronounced compared to reports at air interfaces . This was despite the excess protein presented in solutions (total concentrations of 1 mg/mL were used in these experiments). Therefore this behaviour is unlikely to arise from limited protein availability alone. In addition, our data suggested that assemblies formed at the surface of droplets were relatively homogenous at the single droplet level, although droplet-to-droplet adsorption levels and fluorescence intensities varied more significantly (Figure ). This behaviour could be resulting from a tendency of these two proteins to self-associate and assemble at hydrophobic interfaces with proteins of the same type, as was reported at air interfaces, for which self-segregated domains of b-casein and BSA were observed . The chemical and thermodynamic grounds for such segregation are not clear, but we note that this is unlikely to be associated with significant level of order in corresponding protein layers, as we had previously not observed any evidence for such order in BSA assemblies formed at Novec 7500 interfaces and transferred to TEM grids for imaging . We also note that most droplets imaged featured mixed intensities of both proteins and therefore self-segregation was not found to be dominating protein adsorption at Novec 7500 interfaces.