Structural investigations of poly(ethylene glycol)-dodecylbenzenesulfonic acid complexes in aqueous solutions

The structures arising in mixed colloidal solutions of anionic surfactant dodecylbenzenesulfonic acid (DBSA) and neutral poly(ethylene glycol) (PEG) polymer in water for a wide range of concentrations and different molecular masses of the polymer were studied by small-angle neutron scattering (SANS) and dynamic light scattering (DLS). The micellization behavior of the system near the critical micelle concentration was characterized by fluorescence spectroscopy and measurements of the surface tension of the solutions. The assumption of the coexistence of free micelles, surfactant-polymer complexes in the form of a necklace structure, and polymer coils was confirmed by DLS and SANS. The typical sizes of micelles and complexes were estimated. It was found that there is an impact of PEG molecular mass on the ability of multi-micelle complex formation. The obtained results are important in particular for the PEGylation of magnetic nanoparticles in sterically stabilized aqueous ferrofluids. •Anionic surfactant micelle aggregation with poly(ethylene glycol) was observed.•Influence of poly(ethylene glycol) on the surfactant micellization was analyzed.•Structure and interaction parameters of micellar system with PEG was obtained.•Impact of PEG molecular mass on micelles behavior was concluded.