Light scattering study of the contrasting interaction between ionic surfactants and neutral polymers

The motivation for this work is to study the behavior of surfactants near the critical micelle concentration (CMC) by light scattering (LS) and to possibly reconcile the variously reported properties. Additionally, the effects of the presence of a neutral polymer on the LS phenomena near surfactants CMC are discussed.

An increase inLS as surfactant concentration approaches CMC, followed by a decrease as the concentration was raised, has been observed at least as far back as 1959. Since then, others have reported a scattering peak near the CMC, with differing results concerning its stability, properties, and origins.The interactions of polymers and surfactants - meaning usually ‘binding’ - has been also the subject of fundamental and applied research.

The behavior of anionic sodium dodecyl sulfate and cationic dodecyl trimethyl ammonium chloride and their interaction with neutral polymers are investigated in this work, in two concentration regimes, with respect to the surfactant: around CMC, with focus on the effects the polymer on the large surfactant structures observed in this region; and above CMC, studying the type of association among all components.

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