Liquid–liquid phase separation in multicomponent polymer solutions. I. Statement of the problem and description of methods of calculation



Polymers are complex mixtures that may have widely different compositions even if they contain only components having the same chemical constitution. The effect of the chain length distribution on the phase behavior of polymer solutions in a single solvent is described qualitatively. To obtain a quantitative understanding of these phenomena a numerical calculation method is developed which is based on the Flory-Huggins relation for the free energy of mixing. Some examples are presented, and the accuracy and the reliability of the results are discussed.