Abstract: The role of surfactants in stabilizing the formation of bubbles in foams is studied using a phase-field model The analysis is centered on a van der Walls-Cahn-Hilliard-type energy with an added term accounting for the interplay between the presence of a surfactant density and the creation of interfaces. In particular, it is concluded that the surfactant segregates to the interfaces, and that the prescription of the distribution of surfactant will dictate the locus of interfaces, what is in agreement with experimentation.