Relation between the repulsion of incompatible and compatible polymers in solution and their degree of mixing in the solid state: the memory effect

The incompatible polymer pairs polystyrene (PS)/poly(methyl methacrylate) ( PMMA) and polystyrene (PS)/poly(oxyethylene) (POE) and the compatible polym er pair POE/PMMA have been studied in solution and in the solid state. A cl ose relation is observed between the behaviour in solution and in the solid state for both incompatible and compatible polymer mixtures. When we use a selective solvent and when the molecular masses of the polymers of the mix ture are different, even compatible polymers behave like incompatible polym ers; the obtained films present an important demixing. The opposite is obse rved when the films are obtained by casting from a common solvent and when the two polymers possess similar molecular masses. in this case, even incom patible polymers behave Like compatible polymers. These results confirm the already reported memory effect when we go from the solution to the solid s tate. (C) 2000 Society of Chemical Industry.