Interaction between Cetyl Pyridinium Chloride and Water-Soluble Polymers in Aqueous Solutions
The interaction between cetyl pyridinium chloride and different-molecular-weight poly(vinylpyrrolidone) (PVP) and poly(ethylene glycol) (PEG) polymers has been investigated by means of electrical conductivity and fluorescence probing. No interaction between the low-molecular-weight PVP polymers and the surfactant was detected, whereas a significant interaction was observed between high-molecular-weight PVP polymers or PEG polymers and cetyl pyridinium chloride. The results indicate that polymer-surfactant aggregates start to form at a surfactant concentration higher than the critical micelle concentration of micelles without polymers. In contrast, the degree of ionization and the interface polarity decrease as compared with values of micelles without polymers. The Gibbs free energy associated with the interaction was also calculated. The values show that the addition of polymers stabilizes polymer-surfactant aggregates. Copyright 1997 Academic Press. Copyright 1997Academic Press
Garc&iacute;a-Mateos
I
Facultad de Farmacia, Universidad de Salamanca, Apdo. 449, Salamanca, E-37080, Spain
P&eacute;rez
S
Vel&aacute;zquez
MM