On the Origin of Foam Stability: Understanding from Viscoelasticity of Foaming Solutions and Liquid Films

The foam stability (drainage half-life) of α-olefin sulfonate (AOS) with partially hydrolyzed polyacrylamide (HPAM) or xanthan gum (XG) solution was evaluated by the Warring Blender method. With the increase of polymer (HPAM or XG) concentration, foam stability of the surfactant–polymer complexes increased, and the drainage half-life of AOS-XG foam was higher than that of AOS-HPAM foam at the same polymer and surfactant concentration. With the addition of polymer (HPAM or XG), the viscoelasticity of bulk solution and the liquid film were enhanced. The viscoelasticity of AOS-XG bulk solution and liquid film were both higher than that of AOS-HPAM counterparts.