Changes in Aggregation Patterns Detected by Diffusion, Viscosity, and Surface Tension in Water + 2-(Diethylamino)Ethanol Mixtures at Different Temperatures

Mutual diffusion coefficients for 2-(diethylamino)ethanol (2) in water (1) were experimentally obtained by the Taylor dispersion technique from x2 = 0 to ≈ 0.2, at T = 298 K and T = 303 K. Viscosities and surface tensions were measured in the entire composition range using capillary viscometry and ring tensiometry, respectively. Viscosities were measured at the above temperatures, and surface tensions were measured at intervals of 5 K in the temperature range from (283 to 303) K. Information about intermolecular interactions, hydration modes, and solute aggregation is provided through the combined study of the observed changes in diffusion coefficients, viscosities, and surface tension with composition. Conclusions obtained are compared with those taken from volumetric and optical properties for the same system.