Comparative analysis of complex liquids based on a multi-experimental approach.
A parallel analysis is here presented between the results gathered by the author by means of three different experimental approaches--Dielectric analysis, Thermally Stimulated Depolarization (TSD) and Differential Scanning Calorimetry (DSC)--on some multi-component complex liquids consisting of association structures of self-assembling amphiphiles as, water-in-oil microemulsions. The highly dispersed nature of these systems was evidenced with the dielectric study: a Maxwell-Wagner relaxation was found to characterize this type of systems. The structural evolution of the system, against water addition, was well described by the orientational processes induced in the liquid samples by a nearly static electric field as in the TSD method. The investigation by DSC, besides offering a basic picture of the system's thermodynamics, allowed the measure of the specific heat, at constant pressure, at the higher order percolative phase transition. The comparison between the results obtained on samples processed with identical thermal cycles, once under the action of an impressed electric field as in TSD, and, once in the absence of any impressed electric field as in DSC, did help distinguish three main concentration intervals within which structurally different systems form namely, isotropic microemulsions and two liquid crystalline structures of lyotropic type.
Emulsions and Solubilization
Containing information useful for demonstrating the relation between the function of Hydrophilic Lipophilic Balance (HLB) and solubilization, microemulsions and emulsion stability or inversion, this book covers the effect of temperature on systems containing nonionic surfactants and studies of the surfactant as a function of temperature. The book also demonstrates how the HLB solution properties of the surfactant can be controlled to change from water-soluble to oil-soluble.
The relative permittivity of supercooled water
Approximate relative permittivity data for water down to −35°C have been derived from measurements of the Maxwell–Wagner interfacial polarization which occurs at the surface of emulsified water droplets. Although the emulsifying agent strongly influences this polarization in a complex way, a novel method of data analysis enables the permittivity and conductivity to be obtained in a simple and direct manner. The derived data are in essential agreement with literature data near 0°C. To within an estimated experimental uncertainty of ±2% the present data conform to a critical exponent expression with the same critical temperature (228 K) found for many other properties of supercooled water, though the divergence is very weak.