Solvency effects on polymer-surfactant interactions

Gaining a comprehensive understanding of the properties and functions of surfactant and polymer systems in a range of solvents will support the continued development of new uses for these systems.

Against this background, this study characterised the interaction of the anionic surfactant sodium dodecyl sulphate (SDS) with the nonionic polymer, poly(vinylpyrrolidone) (PVP) in ethanol/water mixtures. A wide range of techniques were used, including surface tension, fluorescence spectroscopy, Nuclear Magnetic Resonance, Electron Paramagnetic Resonance, Small-Angle Neutron Scattering, and viscometry. This enabled properties such as the, critical micelle concentration and critical aggregation concentration (or CMC1) to be determined, as well as measuring the size and shape of micelles formed and of polymer configurations and further establishing trends in these physical properties with solvent composition.

The study then went on to investigate SDS with a non-ionic triblock copolymer, Pluronic P104, in ethanol/water mixtures. This was a more challenging system and yielded some preliminary results, setting the way for further work on the interactions of ethanol with pluronics and surfactants.