Structure, water sorption, and transport properties of crosslinked N-vinyl-2-pyrrolidone/N,N′-methylenebisacrylamide films

Crosslinked N-vinyl-2-pyrrolidone (NVP) free-standing films were prepared by UV-induced photopolymerization in the presence of water using N,N′-methylenebisacrylamide (MBAA) as the crosslinker. A series of crosslinked films were prepared at various prepolymerization water contents and NVP/MBAA ratios. The films underwent phase separation during polymerization. Cryogenic scanning electron microscope (CryoSEM) was used to characterize the morphology of the films. The influence of monomer/crosslinker ratio and prepolymerization water content on morphology and water transport was characterized. Higher water content or higher monomer content in the prepolymerization mixture led to more open structures and, in turn, higher water permeability.