Deformation modes of complex fluid interfaces

The rheology of complex fluid interfaces influences the dynamics of emulsion droplets and foam bubbles, vesicles, polymersomes and polymer microcapsules, biological cells, lung alveoli, or thin liquid films. With recent progress in improved and robust measuring techniques, both the shear and the dilatational viscoelastic properties of interfacial adsorption layers have received much attention. Understanding the relation between interfacial rheology, interface structure, and macroscopic material properties of complex fluids remains a challenge. In this article, the role of these links is discussed for the most important interface deformation modes, shear and dilatation, in the context of adsorption layers formed by surfactants, proteins, nanoparticles and for composite interfaces.