Permeabilities of water, several alcohols, and water/alcohol mixtures through thin films of syndiotactic‐rich poly(vinyl alcohol)

The permeabilities of liquids through syndiotactic‐rich poly(vinyl alcohol) ( s ‐PVA) very thin films (about 0.3 μm) scooped up from the interface of air/aqueous solution were compared with that of casting s ‐PVA films (about 15 μm). The permeability of water decreased with time and the volume of permeate leveled off after 4 or 5 days in both films. In the case of the very thin films, the permeabilities of alcohols decreased with the increase in the molecular weight of alcohol, whereas, in the case of casting films, the permeability of methanol was lower than that of ethanol. In the case of the very thin films, the permeabilities of any water/alcohol (=50/50) mixtures were lower than those of pure water and alcohols. These results were correlated to rearrangement of s ‐PVA molecules, formation of bound water, hydrophobic interaction, and clusterization of small molecules.