INTERACTIONS BETWEEN POLY(ACRYLAMIDE) AND SURFACTANTS OF DIFFERENT HEADGROUP CHARGE

Air/water surface tensions and oil/water interfacial tensions are repo rted for aqueous mixtures of poly(acrylamide) (PAAm) and three differe nt surfactants, i.e. sodium dodecyl sulfate (SDS), cetyltrimethylammon ium bromide (CTAB), and a commercial non-ionic surfactant, Triton X-10 0 (TX-100). Results show a synergistic effect between these surfactant s and the polymer. Oil-in-water emulsification experiments using PAAm- surfactant mixtures showed that the TX-100-PAAm mixture was the most e ffective emulsifier. The emulsification ability of TX-100-PAAm was not affected by pH in the range pH 3-10, implying that hydrophobic intera ctions between TX-100 and PAAm dominate over other mechanisms. At low pH, SDS has an emulsification ability similar to TX-100, and at high p H the effect of CTAB is comparable to that of TX-100. Pressure-area (p i-A) curves and Brewster angle microscopy are used to gain insight int o the interaction mechanism between PAAm and these three surfactants.