Fluorescence Investigations of the Association of PEO-PBO-PEO Triblock Copolymers in the PRESENCE of Ionic Surfactants SDS and CTAB

The interactions of triblock copolymers (TBP), E30B10E30 and E48B10E48 with ionic surfactants, sodium dodecyl sulphate (SDS) and cetyl trimethyl ammonium bromide (CTAB) were investigated employing steady-state fluorescence spectroscopy (SSF). In this study pyrene was used as probe while cetyl pyridinium chloride (CPC) as a quencher. SSF was used for the calculation of first and third vibronic ratio (I1/I3), aggregation number, binding sites, binding constant and free energy of binding. In the presence of TBP, the I1/I3 was found more for SDS as compared to CTAB, predicting that the micro polarity of the solvent decreases in case of CTAB. The aggregation number of polymer/surfactant mixed systems was determined by SSF techniques. The suppression of the TBP association in the presence of surfactant concentration was also ensured by the same technique.