Understanding the properties of adsorbed films at air-liquid or liquid-liquid interfaces is important for formulating stable emulsions and foams in the food, cosmetic, pharmaceutical and coating industries. For example, some proteins are known to denature and form a two-dimensional network at air-liquid and liquid-liquid interfaces. The denaturation process can be examined by measuring the viscoelastic properties of these interfaces. Dynamic rheological experiments are capable of separating the storage (elastic) and loss (viscous) modulus of complex rheological behavior. Both, area changing (dilatational) and constant area (shear) properties can be measured and give valuable information on the mechanical properties of the interface.
In this presentation, two methods for the study of interfacial protein layers are presented; oscillating drop (dilatational) and interfacial shear rheometry (shear). The study presents results on measuring the viscoelastic properties and the adsorption and network formation of protein solutions to interfaces. Time dependent data shows how to determine the gel point of the systems. It also demonstrates how precise control of surface pressure during a measurement makes it possible to model natural systems like cell membranes.
ri.aro@biolinscientific.com
