INFLUENCE OF HYDROPHOBIC COSOLUTES ON AQUEOUS 2-PHASE POLYMER-SURFACTANT SYSTEMS

It is commonly observed that macromolecular mixtures in a common solve nt phase separate with each component enriched in its respective phase . In this case the segregative phase behavior between the anionic poly mer polystyrene sulfonate and the anionic surfactant sodium dodecyl su lfate has been studied in water. In particular, the effect of additive s on the phase behavior has been studied. The additives are sodium chl oride, hexanol, octanol, and octane. With the exception of sodium chlo ride these additives are practically insoluble in mater but they still have a strong impact on the phase behavior. Salt, and alcohols such a s hexanol and octanol, decrease the polymer-surfactant compatibility ( i.e., the extent of the two-phase area increases). Addition of octane enhances the compatibility so that the two-phase area shrinks. The mec hanism by which the additives act is to influence the micellar size. F rom viscosity measurements it has been found that addition of alcohols and salt induces micellar growth whereas addition of an alkane can re duce the micellar size.