The lower critical solution temperature (LCST) of non-polar polymer solutions: An introduction

The phase behavior at high temperatures of non-polar polymer solutions is discussed in a qualitative way in terms of the free volume theory of liquids developed by Prigogine, Patterson and Flory. This theory is necessary to explain the existence of a Lower Critical Solution Temperature (LCST) in non-polar polymer solutions and the related exothermic heats of mixing. The classical theory of polymer solutions and its limits is first reviewed.