FT-IR study of micelle formation in aqueous sodium n-hexanoate solutions

Abstract

The application of Fourier transform infrared (FT-IR) spectroscopy to the study of aqueous surfactant solutions is shown to give valuable information concerning the the self-association of such systems. In the case of aqueous sodium n-hexanoate, progressive aggregation and sodium ion binding are demonstrated to commence at a concentration of approximately 0.75 M. A second inflection point is observed at approximately 1.75 M and is interpreted as marking the transition to a homogeneous micellar solution. The variations in previously reported critical micelle concentration values are rationalized in terms of the sensitivity of the techniques to various states of micelle formation. 26 references.