CTAB 용액의 미세구조와 유변학적 물성에 대한 첨가제의 영향

Abstract

The effect of cosurfactant and NaSal additives on the evolution of microstructure in micellar solution are investigated. The microstructure is developed via two-step shape transitions in micellar solution when the surfactant concentration exceeds a CMC. First, the initial spherical micelles undergo shape transition to rodlike or disclike micelles because the surface characteristics of micelle demand the compact packing as the surfactant concentration increases. The packing density strongly depends on the rate of decrease in the repulsions between micelleheadgroups as well as on temperature. Further increment in the surfactant concentation makes the anisotropic rodlike micelles overlapped one anther. Solutions in these states exhibit non-Newtonian behaviors such as shear thinning. Addition of solubilized additives enhances the transitions which are affected by the concentration and chemical structure of the additive. Presence of cosurfactants with long alkyl chains reduces the repulsion by forming surfactant-alcohol mixed micelles.