Conformational changes at the microemulsion water/oil interface and their influence on the system´s dielectric temperature behavior

The influence of temperature upon the dielectric behavior of a water-in-oil type of microemulsion is investigated in the subzero temperature domain as well as the above-room-temperature range. Thermal analysis by means of differential scanning calorimetry is used in parallel with the dielectric measurements with the aim of providing both a match and a comparison between the behaviour of microemulsion samples under different experimental conditions, using the same temperature program. Particular emphasis is given to the dielectric behavior of the water configuration labeled bound, interphasal, and free that previous work had shown to be distinguished by the melting temperatures of 233, 263, and 273 K, respectively. The dielectric findings are analyzed in the light of the results obtained with surface-pressure/area measurements of flat monolayers, featuring the interface region of the water/oil microemulsion.