There are a number of products and industries around us that depends on the stability of suspensions, emulsions, foams and froth. Paints, pharmaceuticals, cosmetics, personal care and food products all are based on formulations, which require optimum composition and stability for their performance and proper shelf-life. The petrochemical and mineral processing industries often struggle with problems associated with emulsion and froth stability.
Just as rheology is the study of flow in bulk fluids, interfacial rheology is the study of the flow properties of liquid interfaces. These flow properties are important in determining, for example, the behaviour and stability of suspensions, emulsions, froth and foams. The flow properties of liquid interfaces can be influenced by using for example surfactants, polymers, lipids, proteins or particles in the formulation of interest. Interfacial rheological parameters can be determined by changing the area of the interface, and measuring the resulting change in interfacial tension by drop shape analysis. The Theta Optical Tensiometer equipped with a piezoelectric transducer (PD100) is a powerful combination for studying flow behavior and determining interfacial rheological parameters of liquid interfaces.