Abstract
In these days, novel and sophisticated polymers have been developed along with the progress in chemistry. Tochoose the most appropriate material for a separation membrane from the large number of candidates, the presentmethodology of experimental trial and error is no longer enough, instead new design methodology consideringphysicochemical phenomena is required. Because transport phenomenon in polymeric membrane is generallydescribed by the solution–diffusion mechanism, if molecular solubility and diffusivity in polymer can be estimated,molecular permeability and selectivity can be calculated. In the former half of the manuscript, how to estimate per-meable properties of polymeric membrane is described with the example of the pore filling membrane. On the otherhand, molecular diffusivity in polymeric material varies over several orders. So, the prediction of the dynamic physi-cal property is significant concern for the membrane design. To overcome the problem of the previous diffusionmodel that can only be applied for polymer–solvent systems, the incorporation of the microscopic notions of molecu-lar collisions and random walk movement is described in the latter half of the manuscript. The proposed microscopicdiffusion model now can predict molecular diffusivity of gas, solvent, and solute in polymeric systems, that is expect-ed to be applicable to wide range of future membrane design.
