Abstract:

The effects of free and bound water on the dielec. properties of microemulsions prepd. with the non-ionic surfactant Brij 97 were investigated. For the calcn. of the relative amts. of free and bound water, a simple multi-layered dielec. model was applied. The model considers the microemulsion as a sum of three sep. layers consisting of a "dry" microemulsion, free water and bound water, resp. The method is based on dielec. measurements of microemulsions at a frequency for which the dielec. permittivity and the dielec. losses for bound and free water have significantly different magnitudes. The dielec. contribution of free water to the relaxation spectrum of the microemulsion can be obtained, allowing both fractions to be calcd. In contrast to the traditional procedures used for calcn. of bound water from the relaxation spectrum, this method does not involve analyses of overlapping relaxation processes. [on SciFinder(R)]