Composition and Size of Reverse Micelles of Tergitol NP-4 and Tergitol NP-4 + AOT inN-Decane during Evaporation Crystallization of KNO3

Abstract

We have determined the solubilization and crystallization fields of KNO3 for simple (Tergitol NP-4 and AOT) and mixed (Tergitol NP-4 + AOT) microemulsions at 35 °C, depending on water content and concentration of KNO3. An increase in the content of AOT in mixed microemulsions leads to widening of the solubilization field, but the crystallization field narrows up to complete disappearance (in simple microemulsions of AOT). Fourier transform-infrared spectroscopy, photon–correlation spectroscopy, and flame photometry were used to determine the rate of water evaporation (2.6–7.4 μL/min), hydrodynamic diameter of micelles (4.3–10 nm), and the content of water and K+ and Na+ ions in the studied microemulsions at different stages of evaporation crystallization of KNO3. In simple microemulsions of Tergitol NP-4 crystallization begins well before that in mixed microemulsions; in mixed microemulsions the beginning of crystallization requires higher supersaturation (up to 13 M) compared to simple microemulsions (∼4...