Interfacial tension determination of liquid systems in which one of the phases is non-Newtonian using a rheo-optical method

摘要

The interfacial tension between two low-density-difference liquids, one of them being non-Newtonian, was determined using a rheo-optical method with a computer-controlled parallel bands apparatus. This determination is featured measuring the steady-state deformation suffered by a Newtonian drop sheared by a non-Newtonian liquid matrix as a function of the applied shear rate. The application of Taylor's theory to the linear region of deformations, taking into account a mean viscosity of the matrix, enables us to determine the interfacial tension between both liquids as a fitting parameter. Such calculated sigma values were checked for several oils with different viscosities, immersed in the same continuous phase, finding excellent agreement with the conventional drop detachment measurement.