Vapor-induced Crystallization in Alcoholic Sorption using Poly(lactic acid) Films

In this study, the sorption amount of alcohols (ethanol, 1-propanol, and 2-propanol) vapors on poly(lactic acid) (PLA) membrane was measured resulting in high increase in sorption. Sorption amount increases as the molecular volume of vapor decreases in the low-pressure region. The sorption amount of branched 2-propanol is lower than that of linear 1-propanol. In the high-pressure region, the PLA film tends to swell or plasticize as the cluster size increases, thereby increasing sorption. In addition, the alcohol vapor sorbed in the PLA film causes vaporinduced crystallization, which is in contrast to solvent- and thermally-induced crystallization, and forms an unknown crystal structure.