Measuring Techniques and Potential Applications of Interface Rheology

Proteins, surfactants and some polymers adsorb spontaneously at the interface between their aqueous solution and a gas, solid, or liquid phase. The surface layer made this way is characterized by different mechanical properties from the bulk solution, which is determined by surface rheology. The surface layer can undergo dilatational deformation and shear. In general, it can be characterized by both viscous and elastic properties. Surface rheology allows understanding the interaction between molecules, change of molecular conformations or molecular aggregations and diffusion rate of molecules towards the surface layer. There are many publications in which attention is drawn to the possibility of a relationship between surface rheology and foam and emulsion stability. This chapter discusses basic measurement techniques used to determine rheological properties of the sur-face layer, examples of test results, and the potential possibility of their use in practice.