VOLUMETRIC BEHAVIOR OF AQUEOUS FLUORINATED SURFACTANTS AND THEIR MIXTURES WITH HYDROGENATED SURFACTANTS

The mean partial molal volumes of mixed micelles (V-m) and the volume change (Delta V) on mixing were determined from measurements of the density. The value of Delta V is a measure of non-ideality of the mixture. The behaviour of the aqueous mixtures of fluorinated and hydrogenated non-ionic surfactants was reported. At constant hydrophobic (fluorinated and hydrogenated) tails, the mixing in the aggregates may be almost ideal or noticeably non-ideal. The mutual oleophoby of these surfactants is enhanced by a marked dissymetry in the hydrophilic chains particularly in presence of large amounts of water. This results agrees with the conclusion based on the surface tension and x-ray data already reported.