Rheology of Surface Films

Interfacial rheology concerns to the description of the mechanical behavior exhibited by interfaces and the resulting impact of surface properties on the dynamics of complex systems. It deals with the measurement and analysis to providing insights on the response of interfaces to external forces and deformations. Specifically, it focuses on the interface mechanical behavior to understand and quantify the viscoelastic properties of interfaces, including surface tension, shear elasticity, and interfacial viscosity. Especially, rheology of fluid interfaces has a strongly impact on the properties of systems exposing daily phenomena. In the food and beverage sector, interfacial rheology ensures the stability of systems as salad dressings and mayonnaise while also optimizing foam properties in products as whipped creams and ice creams. In pharmaceuticals, it is useful to design drug delivery systems like liposomes, enhancing drug release efficiency. In oil and gas field, it is crucial to enhanced oil recovery methods. Additionally, interface rheology has a key feat in stability and consistency of disperse systems, foaming processes in chemical industry, nanoparticle behavior in materials science, wastewater treatment, cleaning product properties in the surfactant industry, emulsion polymerization in petrochemical sector, and biological interfaces as cell membranes and lipid bilayers, which have applications in drug delivery and diagnostics. The fundamental of interfacial rheology makes a close analogy to three-dimensional rheology, even descriptive models. A pronounced endeavor has been dedicated to improving the rheological delimitation of interfacial films. Dilatational rheology has provided useful information to elucidate compositional effects in mixed interfacial layers, whereas shear rheology has allowed the evaluation of interface structures. On dilatational strains, the bubble and oscillating droplet tensiometry are the most commonly used methods, while oscillating probe and biconus rheometers are more used for shear strains. Interface rheology modelling is an essential tool for understanding the behavior of fluids and soft materials near interfaces.