A comparative behavior of photophysical properties of Pluronic F127 and Triton X-100 with conventional zwitterionic and anionic surfactants

The mixed micellar properties of a triblock copolymer, Pluronic F127, (EO)97(PO)69(EO)97 and a nonionic surfactant, Triton X-100 (TX-100), in aqueous solution with conventional zwitterionic (alkyldimethylammoniopropane sulfonates) and anionic (sodium dodecylsulfate, SDS, and dodecylbenzene sulfonate, SDBS) surfactants were investigated with the help of fluorescence measurements at 25 °C. From the variation of I1/I3 intensity ratio of pyrene fluorescence, the critical micelle concentration (cmc) and other related micellar parameters were determined. Apart from this, photophysical properties of pyrene due to its quenching as well as excimer formation in the interior of the mixed micelles were also studied and explained on the basis of stability of the mixed micelles. It was observed that the mixed micelle formation between zwitterionic/anionic +F127 occurred due to favorable interactions, the magnitude of which increased with the increase in hydrophobicity of zwitterionic component. On the other hand, close to ideal or unfavorable mixing was observed in the mixtures of zwitterionic + TX-100, which was attributed to the incompatibility due to the bulkiness of the hydrophilic groups of zwitterionic and TX-100 components.