To the Methodology of Phase Transition Temperature Determination in Aqueous Solutions of Thermo-Sensitive Polymers

Abstract

An advanced methodology of phase transition determination in aqueous solutions of thermo-sensitive polymers by using of the phase portraits method has been suggested. The methodology allows highly accurate determining the temperature when exactly a half of molecules loses solubility (from the maximum number that can go to another phase state under given conditions). It is shown that since phase transition passes usually in a wide enough temperature interval this indicator should be used as a quantitative parameter that characterizes phase transition process. Additionally the suggested methodology allows introducing one more quantitative parameter that reflects a sharpness of phase transition. The methodology is verified by an example of phase transitions study in aqueous solutions of thermo-sensitive copolymers based on N-vinylpyrrolidone and vinyl propyl ether.