Viscoelasticity and microstructure of non-ionic microemulsions

Non-ionic microemulsions were investigated by viscoelastic measurements in the kHz region. We found that in some parts of the phase diagram our systems consisted of a dispersion of spherical oil doplets, stabilized by a non-ionic surfactant, in a continuous phase of almost pure water. Because of the simplicity of the system used it was relatively easy to interpret our measurements in terms of two rheological models developed by Oldroyd. Using these models, we could calculate the interfacial tension between the continuous and the dispersed phase. In other parts of the phase diagram, however, our results indicate the presence of a fluctuating network of oil-swollen cylindrical micelles.