(334h) A New Instrument for Interfacial Dilational Rheology

The viscoelastic properties of interfaces are believed to be important to the formation of foams and emulsions. They also directly influence the functionality of important biological systems, such as the tear film on eyes and alveoli in the lungs. Because of the importance of interfacial rheology, measurement techniques and mathematical models are needed to understand it. However, methods for measuring interfacial dilational rheology are still not standardized and there are major drawbacks to the instruments commonly used. Here we present a novel design for an interfacial dilational rheometer (IDR) that can generate purely dilational deformation on a planar interface and measure dilational moduli with a resolution as low as ±0.25 mN/m. In this talk we will present data to demonstrate several use cases, such as fundamental studies of soluble and insoluble surfactants, temperature dependence of lung surfactants, correlation to foaming properties of commercial products like milk alternatives and cleaning products.