Dielectric properties of interphasal water in water-in-oil microemulsions

By means of Differential Scanning Calorimetry applied to w/o microemulsions, the experimental evidence has been obtained of the presence of two forms of water, namely, “free” and “interphasal” distinguished by the melting temperatures of, respectively, 273 K and 263 K. In the case of a w/hexadecane microemulsion, the above water con configurations give rise to two separate endotherms upon steady heating of previously frozen samples. The dielectric properties of the system´s water fraction melting at 263 K were studied in the frequency range 5 Hz-50 MHz. The temperature dependence of both ε´ and ε"/ε´ upon the steady cooling of the liquid samples as well as the heating of the frozen ones, was investigated in the interval (303 K - 90 K).