INTERACTIONS BETWEEN POLYVINYLPYRROLIDONE AND CATIONIC GEMINI/CONVENTIONAL SURFACTANTS

The interactions of two gemini surfactants (16-s-16, s=5, 6) and their conventional counterpart cetyltrimethylammonium bromide (CTAB) with polyvinylpyrrolidones (PVP K15 and PVP K90) were investigated using conductivity, steady-state fluorescence, and viscosity techniques. The results indicate that there is no PVP/CTAB complex formation if molecular weight of PVP<15,000. Both PVP K15 and PVP K90 interact with gemini surfactants. The critical aggregation concentration (cac) and critical micelle concentration (cmc) increase with polymer concentration and do not depend on the polymer molecular weight. Fluorescence study shows that the addition of PVP results in a decrease of the aggregation number in all the systems investigated due to the adsorption of the PVP chain in the micelle palisade layer and the ensuing increase of micelle ionization. The viscosity results suggest that the interactions between the surfactants and the polymer affect both inter-polymer-polymer association and chain expansion. [Supplementary materials are available for this article. Go to the publisher's online edition of Chemical Engineering Communications for the following free supplemental resources: additional data tables and figures.]