A sharp maximum in light scattering occurs in many surfactant solutions when they are diluted through their critical micelle concentration (CMC).  This effect has historically been linked to impurities in the micellar solutions.  Monitoring of the scattering and intrinsic viscosity behavior of sodium dodecyl sulfate (SDS) micelles under a gradient dilution when they are deliberately loaded with an impurity (dodecanol) allows unusual features of the scattering maximum to be explored and linked back to micelle behavior. The concentration at which the onset of the maximum occurs, its width, and the scattering amplitude are directly related to the ratio of impurity to surfactant and further correlated with the loading capacity of the micelles. The data suggest that the release of dodecanol nanoparticles as the CMC is approached is responsible for the scattering behavior. The ionic strength of the aqueous solution has extremely strong effects on all the features of the scattering maximum and its relationship to impurity loading capacity and release.  A model for these experimental characteristics is presented in this work.

Light scattering maxima near micellar CMC and relationship to target molecule loading capacity and release

245th National Meeting (2013)

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