Crystalline orientation and molecular transport properties in nanoporous syndiotactic polystyrene films

The orientation of the crystalline delta nanoporous phase in syndiotactic polystyrene films, obtained by different procedures, have been characterized. For both solution cast and biaxially stretched films a high degree of uniplanar orientation, corresponding to the tendency of the ac crystallographic planes, to be parallel to the film plane has been observed and rationalized. According to molecular dynamics simulations of diffusion of small molecules into the delta nanoporous phase, this uniplanar orientation would minimize the molecular diffusivity through the nanoporous crystalline phase.