The present study is based on the interaction between three polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) triblock copolymers namely Pluronics01.81, P84 and F88 (with same PPO Mot Wt. but 10,40 and 80% PEO, respectively) and the ionic surfactants with 12-C chain but different polar head group charge viz. sodium dodecyl sulfate (SDS, anionic), dodecyl trimethylammonium bromide (DTAB, cationic) and N-dodecyl-N, N-dimethyl-3-ammonio-1-propanesulfonate (C12PS, zwitterionic) using plethora of techniques. The most hydrophobic Plutonic (R) L81 (cloud point. CP = 16.5 degrees C (5%w/w)) remains as molecularly dissolved below the CP and forms unstable vesides close to CP, moderately hydrophobic. P84 (CP = 73.6 degrees C), remains molecularly dissolved below 15 degrees C and forms core-shell micelle above critical micelle temperature (CMT) and the highly hydrophilic F88 forms micelles at elevated temperatures. Micellization and dye solubilizing ability improved in the presence of salt (sodium chloride, NaCl). The presence of ionic surfactants leads to small sized surfactant rich micelles with progressive addition as confirmed by dynamic light scattering (DLS) and small angle neutron scattering (SANS). Amongst the three copolymers, P84 (N-agg approximate to 72) showed maximum solubility of dye and lowering power of CMC (CAC < 2 rnM), hence SANS studies were limited to P84 and it was observed that SDS (N-agg approximate to 145) showed stronger interactions with P84 as compared to DTAB (N-agg approximate to 53) and C12PS (N-agg approximate to 83). (C) 2020 Elsevier B.V. All rights reserved.
