Surface modification of zein films

A novel method to derivatize the surface of zein is devised that can modify the water absorption and surface wetting behavior. The reagents used to impart the desired properties in a reasonable amount of time include octenyl succinic anhydride and alkyl and alkenyl ketene dimers. The method is easy to apply and involves baking with an appropriate concentration of a derivatizing agent. Decreased water absorption and increased contact angle with water relative to control demonstrate the advantages this methodology provides. Atomic force microscopy was used to demonstrate that after derivatization the surface of the film became much different, having large globular domains that extended as much as 122 nm above the lowest surface. Given the hydrophobic character of the reagents and their relative incompatibility with zein, it was anticipated that derivatization would be somewhat inhomogeneous.