Micellization and clouding singularity amid the mixture of EO-PO-based star-block copolymer and cationic surfactants in aqueous solution

Abstract

We herein report the micellization study on mixtures of poly(ethylene oxide)-poly(propylene oxide) (PEO-PPO) star-block copolymer, Tetronics®1304 (T1304) with several cationic conventional and Gemini surfactants (GS) using plethora of physicochemical techniques viz. cloud point (CP), tensiometry, fluorescence, dynamic light scattering (DLS) and small angle neutron scattering (SANS). The results indicate resilient interactions of T1304 with GS in comparison to the conventional analogues with similar alkyl chain length. The presence of cationic surfactants, at lower temperature, induces micellization. Hence, a significant drop can be noted in the critical micellization temperature (CMT) of T1304 as observed from the spectral study. However, in the post-micellar regime, the presence of cationic surfactants enhance the surface charge on the copolymeric micelle which leads to the micellar breakdown resulting into the formation of mixed micelles. Addition of salt, on the contrary, compensated the effect of surfactants and counteracted the hydrophilicity generated in the presence of surfactants.