Effects of surfactant on the molecules of different polarity of solubilization: Based on the study of micellar microscopic morphology mechanism

Abstract

Determining the macro-solubilization capacities and micro-mechanism of surfactant micelles with low concentration is significant for the optimization of the medium of displacement and the further enhanced oil recovery. In this study, the solubilization capacities and interaction of polar anisole, nonpolar white oil and kerosene (polar and nonpolar) in SDBS and industrial betaine were compared from microscopic to macroscopic point of view with cryogenic transmission electron microscopy, dynamic light scattering and UV–Vis's spectroscopy. The study finds that the solubilization capacities were positively correlated with the concentration of micelles and the polar of molecules. Considering the importance of morphology of micelles to the solubilization capacities, and the morphology of micelles gradually changed from spherical to vesicle with increasing concentration. And the size of micelles was determined, and size were roughly in common with the concentration below 1 wt% or else the size of betaine was bigger than that of SDBS, which indicated that betaine might be larger and more likely to form vesicles than SDBS at the same concentration. Moreover, anisole is localized in the surface of micelles and size of solubilizing anisole was the biggest, which indicates the solubilization maxima was positively correlated with the volume of swelling micelle. These results imply that the concentration, morphology and solubilization location of micelles appear to important factors affecting the solubilization performance of surfactant. • Solubilization of micelles: The solubilization capacity of betaine and SDBS is positively correlated with concentration of surfactance and that of SDBS was greatly higher than betaine at same concentration no matter what additions solubilized. • Morphology of micelles: Morphology of micelles gradually changed from spherical to vesicle with increasing concentration. • Size of micelles: The type of particle diameters indicates slightly that the ability of morphological transformation for SDBS is better than betaine solution with medium concentration. For high concentration of micelles, the conclusion is the opposite. • Solubilization site: The polar composition of anisole mainly solubilized in the surface of micelles and the nonpolar of white oil solubilized in the core.