DIFFUSION-INDUCED PHASE-SEPARATION WITH CRYSTALLIZABLE NYLONS .2. RELATION TO FINAL MEMBRANE MORPHOLOGY

Intermediate stages during membrane formation by means of immersion pr ecipitation were studied by cryo-substitution for the system nylon 4,6 , formic acid and water. The presence, nature and size of solid partic les was determined as a function of time and of the distance from the interface. The spherulitic nature of these particles was confirmed by staining the samples. It was shown that at a relatively low nucleation density the concentration profile in the film was hardly influenced b y a starting phase separation process, while in a situation with a rel atively high number of nuclei per volume concentration patterns must b e considerable altered.