Dielectric analysis and Differential Scanning Calorimetry of water-in-oil microemulsions

The system investigated is a multicomponent thermodynamically stable liquid consisting of water spherical droplets, (≈ 10 nm diameter), stabilized by a surfactant shell and dispersed in a continuous oil phase (microemulsions). A comparative analysis is carried out among the results obtained with three different experimental approaches, namely, dielectric analysis, Thermally Stimulated Depolarization, and Differential Scanning Calorimetry. The different measurement procedures are briefly described. The attention was focused on the system water concentration. Two microemulsions, differing only in the oil used as continuous phase, were studied. For any concentration a comparison between the results obtained with the different experimental methods was undertaken. The evolution with water addition of the water/oil interphase region was analysed in some detail.