takes place when the surfactant concentration is higher than a The interaction between cetyl pyridinium chloride and differentvalue termed the critical aggregation concentration (CAC). molecular-weight poly(vinylpyrrolidone) (PVP) and poly(ethyl-Then, there is binding of the surfactant onto the polymer in ene glycol) (PEG) polymers has been investigated by means of the form of aggregates (1). Once the polymer is saturated electrical conductivity and fluorescence probing. No interaction with the surfactant, the excess of surfactant molecules forms between the low-molecular-weight PVP polymers and the surfacfree micelles and at higher surfactant concentrations polytant was detected, whereas a significant interaction was observed mer-bound aggregates coexist with free micelles.
between high-molecular-weight PVP polymers or PEG polymers
In polyelectrolyte oppositely charged surfactant systems, and cetyl pyridinium chloride. The results indicate that polymerthe interaction clearly results from strong coulombic forces.
surfactant aggregates start to form at a surfactant concentration higher than the critical micelle concentration of micelles without In contrast to nonionic polymer systems, the interaction leads polymers. In contrast, the degree of ionization and the interface to phase separation. This fact limits the studies to surfactant polarity decrease as compared with values of micelles without concentrations close to the critical micelle concentration polymers. The Gibbs free energy associated with the interaction (CMC). The interaction begins at surfactant concentrations was also calculated. The values show that the addition of polymers below the CMC of the pure surfactant. At high polyelectrostabilizes polymer-surfactant aggregates. ᭧ 1997 Academic Press lyte concentrations a second, gel-like, liquid phase starts to Key Words: cetyl pyridinium chloride; poly(vinylpyrrolidone); form and can be separated at surfactant concentrations much poly(ethylene glycol); pyrene 1-carboxaldehyde; polymer-surfaclower than those corresponding to charge neutralization. The tant interaction; electrical conductivity; fluorescence probing.
phase behavior (10) and surfactant aggregation number (11) have been obtained for some surfactant-polyelectrolyte systems.