How come egg and oil will turn into a nice emulsion called mayonnaise when mixed, while water and oil will unavoidably separate into two different phases no matter how vigorously you stir? And is there a way to predict the stability of such phase-mixtures?

In this episode of Science on surfaces we talk to Dr. Susanna Lauren at Biolin Scientific about interfacial rheology and how this can be used to predict emulsion and foam stability. Susanna did her Ph.D. on superhydrophobic surfaces and microfluidics and she is an expert on surface-related phenomena, such as surface tension, wettability, adhesion, and interfacial rheology.

Susanna explains key terminology such as viscosity, stabilization of interfaces, and surface-active molecules, which then leads us to the discussion of how emulsions and foams form. Susanna then moves on to explain in what situations, and why, it is important to be able to measure emulsion and foam stabilities and how this information can be used. She also describes how these measurements can be performed using either of the two approaches of shear- or dilatational methods.

Thanks for listening! If you are interested in surface and interface science and related topics, you should check out our blog - the Surface Science blog

19. Interfacial rheology – predicting product shelf lives and unwanted emulsion formation