Oscillatory deep channel interfacial rheometer

An interfacial rheometer to measure the dynamic response of a liquid–liquid interface subjected to a small amplitude oscillatory shear stress is described. Experiments are conducted in a deep channel rheometer fitted with an oscillatory floor. This instrument is used to examine the rheological behavior of interfaces in the presence of surfactants. Rheological parameters are calculated from a hydrodynamic analysis incorporating interfacial rheological models. It is demonstrated here that an adsorbed layer of macromolecular surfactants at an oil–water interface is viscoelastic even though the adjacent phases are Newtonian.