were tested. These films were prepared by a classical solvent-casting procedure. By
changing the composition and the type of casting solution (ie tetrahydrofurane, dioxane,
dimethyl formamide-tetrahydrofurane, tetrahydrofurane-dioxane, etc.) PU films with different
physical and chemical bulk and surface structures were obtained. Structural properties of
these films were investigated by scanning electron microscopy, equilibrium swelling …