Investigating the Influence of Some Polymers on Micellization Behavior of Sodium Caprylate and Cetyl Pyridinium Chloride

Conductivity and viscosity measurements at 298.15 K were used to investigate the micellization behaviour of anionic surfactant sodium caprylate (SCAP) and cationic surfactant cetyl pyridinium chloride (CPC) in the presence of polymers (polyvinyl pyrrolidone, Tween-20, Tween-40, Tween-60, and Tween-80) in aqueous solutions. For both surfactants, the critical micellar concentration (CMC), critical aggregation concentration (CAC), and polymer saturation point (PSP) have been determined in water and aqueous polymer solutions of various concentrations. The CAC values for both surfactants decreased somewhat as the polymer concentration increased, however the PSP values stayed nearly constant. The degree of ionization (\(\alpha\)) and standard free energy of transfer (\(\triangle\)Go) have been estimated. \(\triangle\)Go values were discovered to decrease as polymer concentrations increased. The relative viscosity, \(\eta\), for the above systems has been determined as well at 298.15 K in various polymer solutions. The maximum value of \(\eta\)I/\(\eta\)I,max (\(\eta\)I is the interaction viscosity) as a function of R (ratio of concentration of surfactant to that of polymer), shifts towards the lower values of R with the increase in polymer concentration. The findings were explored in terms of the numerous interactions that take place in these systems.