Cells and Materials


A peculiar textured structure was found by scanning electron microscopic (SEM) observation on polymer films surface-grafted with water-soluble polyacrylamide and poly(N,N-dimethylacrylamide) after exposure to ozone. The grafted surface became very hydrophilic and highly lubricated when brought into contact with water, due to hydration of the grafted surface layer. Unless water was present, the surface did not become slippery at all. SEM of the grafted surface revealed different profiles, depending on the graft density as well as the process of drying prior to the SEM observation. There was no significant difference between the virgin and the surface-grafted film, when air-dried under the ambient condition. However, when the surface was freeze-dried following immersion in water, the SEM micrograph of surface-grafted films exhibited a textured structure, probably due to partial aggregation of the water-soluble graft chains to micro-domain, caused by freezing of water in the graft layer.